12 multiple-choice questions, progressively harder.
Solve ∣2x−3∣=7|2x - 3| = 7∣2x−3∣=7.
Solution
Correct answer: A
The right side is positive, so split into two cases.
2x−3=7or2x−3=−72x - 3 = 7 \quad \text{or} \quad 2x - 3 = -72x−3=7or2x−3=−7
The first gives 2x=102x = 102x=10, so x=5x = 5x=5; the second gives 2x=−42x = -42x=−4, so x=−2x = -2x=−2.
The vertex of y=∣x−1∣+4y = |x - 1| + 4y=∣x−1∣+4 is at which point?
Correct answer: B
Match to y=a∣x−h∣+ky = a|x - h| + ky=a∣x−h∣+k, where the vertex is (h,k)(h, k)(h,k).
(h,k)=(1,4)(h, k) = (1, 4)(h,k)=(1,4)
The inside x−1x - 1x−1 gives h=1h = 1h=1 and the added 444 gives k=4k = 4k=4.
Solve ∣x+5∣=2|x + 5| = 2∣x+5∣=2.
Correct answer: C
Split the positive right side into two cases.
x+5=2orx+5=−2x + 5 = 2 \quad \text{or} \quad x + 5 = -2x+5=2orx+5=−2
The first gives x=−3x = -3x=−3; the second gives x=−7x = -7x=−7.
Solve 2∣x∣=102|x| = 102∣x∣=10.
Isolate the bars first by dividing by 222.
∣x∣=5 ⇒ x=5 or x=−5|x| = 5 \;\Rightarrow\; x = 5 \text{ or } x = -5∣x∣=5⇒x=5 or x=−5
The vertex of y=−∣x−2∣+5y = -|x - 2| + 5y=−∣x−2∣+5 is at which point?
Correct answer: D
Match to y=a∣x−h∣+ky = a|x - h| + ky=a∣x−h∣+k. The inside x−2x - 2x−2 gives h=2h = 2h=2 and the constant is k=5k = 5k=5.
(h,k)=(2,5)(h, k) = (2, 5)(h,k)=(2,5)
The negative sign flips the opening direction but does not move the vertex.
Solve ∣3x∣=12|3x| = 12∣3x∣=12.
The inside is 3x3x3x, so set it equal to 121212 and to −12-12−12.
3x=12 or 3x=−12 ⇒ x=4 or x=−43x = 12 \text{ or } 3x = -12 \;\Rightarrow\; x = 4 \text{ or } x = -43x=12 or 3x=−12⇒x=4 or x=−4
How many solutions does ∣x−5∣=−1|x - 5| = -1∣x−5∣=−1 have?
An absolute value is never negative, so it cannot equal −1-1−1.
∣x−5∣≥0>−1|x - 5| \ge 0 > -1∣x−5∣≥0>−1
The negative right side means there is no solution.
What is the range of y=−∣x∣+2y = -|x| + 2y=−∣x∣+2?
The vertex is at height 222, and the minus sign opens the V downward.
a<0 ⇒ y≤k=2a < 0 \;\Rightarrow\; y \le k = 2a<0⇒y≤k=2
Starting at the top point 222, the outputs only decrease.
Solve ∣x−1∣=0|x - 1| = 0∣x−1∣=0.
Only zero has absolute value zero, so the inside must be zero.
x−1=0 ⇒ x=1x - 1 = 0 \;\Rightarrow\; x = 1x−1=0⇒x=1
A right side of 000 gives exactly one solution.
Compared to y=∣x∣y = |x|y=∣x∣, the graph of y=2∣x∣y = 2|x|y=2∣x∣ is which of these?
The factor ∣a∣=2|a| = 2∣a∣=2 doubles each branch's slope.
slopes ±1⟶±2\text{slopes } \pm 1 \longrightarrow \pm 2slopes ±1⟶±2
Steeper branches make a narrower V; the vertex stays at the origin.
Solve ∣2x+1∣=5|2x + 1| = 5∣2x+1∣=5.
2x+1=5or2x+1=−52x + 1 = 5 \quad \text{or} \quad 2x + 1 = -52x+1=5or2x+1=−5
The first gives 2x=42x = 42x=4, so x=2x = 2x=2; the second gives 2x=−62x = -62x=−6, so x=−3x = -3x=−3.
Solve ∣x∣<4|x| < 4∣x∣<4.
A 'less than' absolute value traps the inside within a band around zero.
−4<x<4-4 < x < 4−4<x<4
Every number closer than four units to zero qualifies.
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