ACT Math — Algebra Domain Test
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Question 1
What is the value of \(x\) if \(3x+7=25\)?
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Subtract 7: \(3x=18\).
Divide by 3: \(x=18/3=6\).
Answer: B
Question 2
Which expression is equivalent to \(4(2x-3)+5\)?
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Distribute and combine constants: \(4(2x-3)+5=8x-12+5=8x-7\).
Answer: F
Question 3
If \(5x-4=2x+17\), what is \(x\)?
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Subtract \(2x\) and add 4: \(3x=21\), so \(x=7\).
Answer: C
Question 4
For which value of \(x\) is \(2x+5<17\) true?
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Subtract 5: \(2x<12\).
Divide by 2: \(x<12/2\), so \(x<6\).
Answer: J
Question 5
Which expression is equivalent to \(x^2+7x+12\)?
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The numbers 3 and 4 multiply to 12 and add to 7: \(x^2+7x+12=(x+3)(x+4)\).
Answer: A
Question 6
The equation \(y=3x-5\) is in slope-intercept form. What is the slope of the line?
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In \(y=mx+b\), the coefficient \(m\) is the slope.
Here \(m=3\).
Answer: J
Question 7
A taxi company charges a fixed fee of \(\$4\) plus \(\$2\) per mile. Which equation gives the total cost \(C\), in dollars, for a trip of \(m\) miles?
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The variable cost is \(2m\) and the fixed fee is 4: \(C=2m+4\).
Answer: D
Question 8
The line shown passes through \((-2,-1)\) and \((2,3)\). What is the slope of the line?
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Use the slope formula \(m=\frac{y_2-y_1}{x_2-x_1}\).
Substitute the two points: \(m=\frac{3-(-1)}{2-(-2)}=\frac44=1\).
Answer: H
Question 9
If \(3a+2b=18\) and \(a=4\), what is the value of \(b\)?
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Substitute \(a=4\): \(12+2b=18\), so \(2b=6\) and \(b=3\).
Answer: C
Question 10
Which equation is equivalent to \(4x-3y=12\) when solved for \(y\)?
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\(4x-3y=12\) gives \(-3y=12-4x\): \(y=\frac43x-4\).
Answer: F
Question 11
A theater sold 120 tickets for a performance. Adult tickets cost \(\$12\) and student tickets cost \(\$8\). Total ticket revenue was \(\$1,200\). How many adult tickets were sold?
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Let \(a\) be adult tickets and \(s\) student tickets: then \(a+s=120\) and \(12a+8s=1200\).
Substitute \(s=120-a\): \(12a+960-8a=1200\). \(4a=240\) and \(a=60\).
Answer: C
Question 12
What is the solution set of \(|2x-3|=7\)?
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Solve \(2x-3=7\) or \(2x-3=-7\).
These give \(x=5\) or \(x=-2\).
Answer: J
Question 13
Which expression is equivalent to \((2x-5)(x+3)\)?
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Multiply: \(2x^2+6x-5x-15=2x^2+x-15\).
Answer: A
Question 14
The graph shows two lines that intersect at \((2,3)\). Which ordered pair is the solution to the corresponding system of equations?
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The solution to a graphed system is the intersection point.
The lines intersect at \((2,3)\).
Answer: H
Question 15
For \(x\ne4\), which expression is equivalent to \(\frac{x^2-16}{x-4}\)?
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Factor the numerator: \(x^2-16=(x-4)(x+4)\).
Cancel \(x-4\) to get \(x+4\).
Answer: B
Question 16
The system \(2x+ky=6\) and \(4x+6y=12\) has infinitely many solutions. What is the value of \(k\)?
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For infinitely many solutions, the first equation multiplied by 2 must equal the second.
Thus \(2k=6\), so \(k=3\).
Answer: G
Question 17
The roots of \(x^2-px+18=0\) are positive integers that differ by 3. What is the value of \(p\)?
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The positive factor pair of 18 that differs by 3 is 3 and 6.
Their sum is \(p\), so \(p=9\).
Answer: D
Question 18
The graph of \(y=a(x-2)^2-3\) passes through \((0,5)\), as shown. What is the value of \(a\)?
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Substitute \((0,5)\): \(5=a(0-2)^2-3=4a-3\).
Thus \(8=4a\) and \(a=2\).
Answer: G
Question 19
If \(\frac{3}{x-1}=\frac{2}{x+2}\), what is the value of \(x\)?
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Cross-multiply: \(3(x+2)=2(x-1)\).
Then \(3x+6=2x-2\), so \(x=-8\).
Answer: A
Question 20
For what value of \(c\) does the equation \(x^2-6x+c=0\) have exactly one real solution?
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Exactly one real solution occurs when the discriminant is 0: \((-6)^2-4(1)c=0\).
Thus \(36-4c=0\), so \(c=9\).
Answer: G