Answer
$-2$.
Work Step by Step
The given equation is
$\Rightarrow 8(x+6)-10+r=3(x+12)+5x$
Use distributive property.
$\Rightarrow 8x+48-10+r=3x+36+5x$
Add like terms.
$\Rightarrow 8x+38+r=8x+36$
Add $-8x-38$ to each side.
$\Rightarrow 8x+38+r-8x-38=8x+36-8x-38$
Simplify.
$\Rightarrow r=-2$
Hence, the value of $r$ is $-2$.
