Question 104564
{{{4 + abs(r+2) = 7}}}
{{{4 - 4 + abs(r+2) = 7 - 4}}} Additive inverse of 4. 
{{{abs(r+2) = 3}}} Simplify.
The absolute value function is defined as 
{{{abs(x)=x}}} if {{{x>=0}}} and
{{{abs(x)=-x}}} if {{{x<0}}}
Since we don't know the value of (r+2), we solve for both cases.
Assume {{{(r+2)>=0}}}, then
{{{abs(r+2)=r+2}}}
{{{r+2=3}}}
{{{r=1}}}
Assume {{{(r+2)<0}}}, then
{{{abs(r+2)=-(r+2)}}}
{{{-(r+2)=3}}}
{{{-r-2=3}}}
{{{-r=5}}}
{{{r=-5}}}
Check your answers.
{{{4 + abs(r+2) = 7}}}
r=1
{{{4 + abs(1+2) = 7}}}
{{{4 + abs(3) = 7}}}
{{{4 + 3 = 7}}}
{{{7 = 7}}}
Good answer.
r=-5
{{{4 + abs(-5+2) = 7}}}
{{{4 + abs(-3) = 7}}}
{{{4 + 3 = 7}}}
{{{7 = 7}}}
Good answer.