Answer:
[tex]4.\\\text{E. }x=5, x=-6,\\\\5.\\\text{A. }x=7, x=-3\\\\\text{18.}\\\text{D. No mistakes.}[/tex]
Step-by-step explanation:
For [tex]a=|b|[/tex], there are two cases:
[tex]\begin{cases}a=b,\\a=-b\end{cases}[/tex]
Question 4:
Given [tex]5|2x+1|=55[/tex],
Divide both sides by 5:
[tex]|2x+1|=11[/tex]
Divide into two cases and solve:
[tex]\begin{cases}2x+1=11,2x=10, x=\boxed{5}\\-(2x+1)=11,2x+1=-11, 2x=-12, x=\boxed{-6}\end{cases}[/tex]
Therefore, the solutions to this equation are [tex]\boxed{\text{E. }x=5, x=-6}[/tex].
Question 5:
Given [tex]\frac{1}{2}|4x-8|-7=3[/tex],
Add 7 to both sides:
[tex]\frac{1}{2}|4x-8|=10[/tex]
Multiply both sides by 2:
[tex]|4x-8|=20[/tex]
Divide into two cases and solve:
[tex]\begin{cases}4x-8=20,4x=28, x=\boxed{7}\\-(4x-8)=20, 4x-8=-20, 4x=-12, x=\boxed{-3}\end{cases}[/tex]
Therefore, the solutions to this equation are [tex]\boxed{\text{A. }x=7, x=-3}[/tex]
Question 18:
There are no mistakes in the solution shown. The answer properly isolates the term with absolute value with no algebraic mistakes. Following that, the answer divides the equation into both absolute value cases and solves algebraically correctly. Therefore, the correct answer is [tex]\boxed{\text{D. No mistakes.}}[/tex]
