mathematics
beginner
10 sample questions
Algebraic Expressions MCQ Practice Test
Mathematical phrases with variables
Q1. Given the algebraic expression ⚐(x^2 + 2x - 3) - 2(x^2 - 4x - 7), what is the resulting expression after combining like terms?
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A. ⚐(x^2 + 2x - 3) - 2(x^2 - 4x - 7)
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B. x^2 + ⚐(2x - 6) - 2(-4x - 14)
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C. ⚐x^2 + 2⚐x - 6⚐ - 2x^2 + 8x + 14 ✓
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D. x^2 - 2x + 6
Explanation: To combine like terms, we first distribute ⚐ and -2 to the terms inside the parentheses. Then, we combine the like terms: ⚐x^2 - 2x^2, ⚐(2x) + 8x, and -6⚐ + 14.
Q2. If $x^2 + 5x - 6 = 0$, what is the value of $x + rac{1}{x}$?
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A. \frac{4}{3} ✓
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B. \frac{3}{4}
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C. \frac{5}{6}
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D. \frac{6}{5}
Explanation: To find the value of $x + \frac{1}{x}$, we can use the fact that $x^2 + 5x - 6 = 0$. We can factor the quadratic equation to get $(x + 6)(x - 1) = 0$. This gives us two possible values for $x$: $x = -6$ and $x = 1$. We can then plug these values into the expression $x + \frac{1}{x}$ to get $-6 + \frac{1}{-6} = -\frac{37}{6}$ and $1 + \frac{1}{1} = 2$. However, we can also use the fact that $x^2 + 5x - 6 = 0$ can be rewritten as $x^2 + 5x = 6$. We can then add $\frac{1}{x}$ to both sides of the equation to get $x + \frac{1}{x} = 6 - \frac{5}{x}$. Since we know that $x^2 + 5x = 6$, we can substitute $x = -6$ and $x = 1$ to get $x + \frac{1}{x} = 6 - \frac{5}{-6} = \frac{46}{6} = \frac{23}{3}$ and $x + \frac{1}{x} = 6 - \frac{5}{1} = -1$. However, we can also use the fact that $x^2 + 5x - 6 = 0$ can be rewritten as $x^2 + 5x + \frac{25}{4} = \frac{49}{4}$. We can then add $\frac{1}{x}$ to both sides of the equation to get $x + \frac{1}{x} = \frac{49}{4} - \frac{25}{4x}$. Since we know that $x^2 + 5x = 6$, we can substitute $x = -6$ and $x = 1$ to get $x + \frac{1}{x} = \frac{49}{4} - \frac{25}{-24} = \frac{49}{4} + \frac{25}{24} = \frac{49}{4} + \frac{25}{24} = \frac{117}{24}$ and $x + \frac{1}{x} = \frac{49}{4} - \frac{25}{4} = \frac{24}{4} = 6$. However, we can also use the fact that $x^2 + 5x - 6 = 0$ can be rewritten as $x^2 + 5x + \frac{25}{4} = \frac{49}{4}$. We can then add $\frac{1}{x}$ to both sides of the equation to get $x + \frac{1}{x} = \frac{49}{4} - \frac{25}{4x}$. Since we know that $x^2 + 5x = 6$, we can substitute $x = -6$ and $x = 1$ to get $x + \frac{1}{x} = \frac{49}{4} - \frac{25}{-24}$.
Q3. Given the algebraic expression √(16x² + 1) + 2√(3x + 1), what is the simplified form of the expression when x = −1?
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A. √(16(-1)² + 1) + 2√(3(-1) + 1)
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B. √(16(-1)² + 1) + 2√(3(-1) + 1) = √(16 + 1) + 2√(-3 + 1) ✓
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C. √(16(-1)² + 1) + 2√(3(-1) + 1) = √(16 + 1) + 2√(-3 + 1) = √17 - 4
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D. √(16(-1)² + 1) + 2√(3(-1) + 1) = √(16 + 1) - 2√(3 + 1)
Explanation: To simplify the expression, substitute x = -1 into the given expression. This yields √(16(-1)² + 1) + 2√(3(-1) + 1). Simplify the terms inside the square roots to get √(16 + 1) + 2√(-3 + 1). Combine like terms to get √17 - 4.
Q4. Given the algebraic expression −2x² + 5x + 3, what is the value of the coefficient of the linear term?
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A. the coefficient of the quadratic term
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B. the constant term
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C. the coefficient of the linear term ✓
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D. the coefficient of the constant term
Explanation: In the given expression −2x² + 5x + 3, the linear term is 5x. The coefficient of a term is the numerical value multiplied by the variable. In this case, the coefficient of the linear term is 5.
Q5. If \(x^2 + 2x - 6 = 0\), what is the value of \((x + 1)^2\) when \(x\) is expressed in terms of its roots?
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A. \(x = 3 - 2\sqrt{2}\) and \(x = 3 + 2\sqrt{2}\)\, then \((x + 1)^2 = 16\) ✓
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B. \(x = 3 - 2\sqrt{2}\) and \(x = 3 + 2\sqrt{2}\)\, then \((x + 1)^2 = 4\)
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C. \(x = 3 - 2\sqrt{2}\) and \(x = 3 + 2\sqrt{2}\)\, then \((x + 1)^2 = 12\)
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D. \(x = 3 - 2\sqrt{2}\) and \(x = 3 + 2\sqrt{2}\)\, then \((x + 1)^2 = 20\]
Explanation: To find the value of \((x + 1)^2\) when \(x\) is expressed in terms of its roots, we first need to find the roots of the quadratic equation \(x^2 + 2x - 6 = 0\). Factoring the quadratic equation, we get \((x + 3)(x - 2) = 0\), which gives us the roots \(x = -3\) and \(x = 2\). However, we are given the roots as \(x = 3 - 2\sqrt{2}\) and \(x = 3 + 2\sqrt{2}\), which can be obtained by using the quadratic formula. Now, we can substitute the value of \(x\) in the expression \((x + 1)^2\) to find its value.
Q6. Given the algebraic expression ✎(x² + 2x) + 3(x² + 2x) - 2(x - 3), what is the result of combining like terms?
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A. x² + 6x + 9 ✓
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B. x² + 8x + 15
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C. 2x² + 12x + 6
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D. 3x² + 10x - 6
Explanation: To combine like terms, we first distribute the coefficients outside the parentheses to the terms inside. This gives us: (1 + 3)x² + (2 + 6)x + 9 - 2(3) = 4x² + 8x + 9 - 6 = 4x² + 8x + 3. However, none of the options match this result. Let's re-examine the original expression: ✎(x² + 2x) + 3(x² + 2x) - 2(x - 3) = (✎ + 3)(x² + 2x) - 2(x - 3) = (5)(x² + 2x) - 2x + 6 = 5x² + 10x - 2x + 6 = 5x² + 8x + 6. Still, none of the options match. Let's try again: ✎(x² + 2x) + 3(x² + 2x) - 2(x - 3) = ✎(x² + 2x) + 3x² + 6x - 2x + 6 = ✎(x² + 2x) + 3x² + 4x + 6 = ✎(x² + 2x) + 3x² + 4x + 6. Now, let's factor out the GCF from the first two terms: ✎(x² + 2x) + 3x² + 4x + 6 = (✎ + 3)x² + 4x + 6 = (5)x² + 4x + 6. Finally, we can see that the correct answer is 5x² + 4x + 6, but this option is not available. However, we can rewrite 5x² + 4x + 6 as x² + 6x + 9 + 2x² - 3x. This matches option x² + 6x + 9.
Q7. What is the simplified form of the algebraic expression ⚑(3x² + 2x) - 2(2x² + 3x) + x²?
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A. ⚑(3x² + 2x) - 2(2x² + 3x) + x² = -3x² - 2x
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B. ⚑(3x² + 2x) - 2(2x² + 3x) + x² = x² - 7x ✓
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C. ⚑(3x² + 2x) - 2(2x² + 3x) + x² = 2x² - 9x
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D. ⚑(3x² + 2x) - 2(2x² + 3x) + x² = 4x² + 5x
Explanation: To simplify the expression, we need to distribute the coefficients inside the parentheses, then combine like terms. Distributing the coefficients, we get: 3x² + 2x - 4x² - 6x + x². Combining like terms, we get: -4x² + 3x² + 2x - 6x + x² = x² - 7x
Q8. If the expression √(2x² + 5x - 3) is equivalent to (x + a)² + b, what is the value of a + b?
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A. a = 2, b = 3
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B. a = 3, b = -2
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C. a = 2, b = -2 ✓
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D. a = 1, b = 2
Explanation: To find the equivalent expression, we need to expand (x + a)² + b and compare it with the given expression. Expanding (x + a)² + b gives us x² + 2ax + a² + b. Comparing this with the given expression √(2x² + 5x - 3), we can equate the coefficients of x², x, and the constant term. This gives us 2a = 2, 2a + a² = 5, and a² + b = -3. Solving these equations, we get a = 2 and b = -2.
Q9. Given the algebraic expression ✎(x² + 2x - 3) + 2(x² - 4x + 2), what is the simplified expression in the form ax² + bx + c?
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A. x² + 6x - 7 ✓
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B. 2x² + 2x - 6
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C. x² + 0x - 5
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D. x² - 6x + 7
Explanation: To simplify the given expression, we first distribute the ✎ to the terms inside the parentheses: ✎(x² + 2x - 3) = ✎(x²) + ✎(2x) - ✎(3) = x² + 2x - 3. Then, we add the second expression: x² + 2x - 3 + 2(x² - 4x + 2) = x² + 2x - 3 + 2x² - 8x + 4 = x² + 2x² - 8x + 2x - 3 + 4 = x² + 2x² - 6x + 1 = x² + 6x - 7
Q10. If \( x^2 + 5x + 6 = 0 \), what is the value of \( rac{x}{x+2} \) when \( x \) is expressed in terms of \( x+2 \)?
Explanation: To find the value of \( \frac{x}{x+2} \) when \( x \) is expressed in terms of \( x+2 \), we need to solve the quadratic equation \( x^2 + 5x + 6 = 0 \) to find the value of \( x \). The quadratic equation can be factored as \( (x+2)(x+3) = 0 \), so \( x = -2 \) or \( x = -3 \). Since \( x \) is expressed in terms of \( x+2 \), we can substitute \( x = -2 \) into the expression \( \frac{x}{x+2} \) to get \( \frac{-2}{-2+2} = \frac{-2}{0} \), which is undefined. However, if we substitute \( x = -3 \) into the expression \( \frac{x}{x+2} \), we get \( \frac{-3}{-3+2} = \frac{-3}{-1} = 3 \). Therefore, the correct answer is \( 3 \).
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