Question

Solve : | -2r - 1 | = 11

Answer 1

Given the equation :

$|-2r-1|=11$

The given absolute function will be written as :

$-2r-1=11,-2r-1=-11$

So, for the first equation :

$\begin{gathered} -2r-1=11 \\ -2r=11+1 \\ -2r=12 \\ r=\frac{12}{-2}=-6 \end{gathered}$

For the second equation :

$\begin{gathered} -2r-1=-11 \\ -2r=-11+1 \\ -2r=-10 \\ r=\frac{-10}{-2}=5 \end{gathered}$

So, the answer is : r = { -6 , 5 }