Question

i need help its math

Answer 1

Evaluate the left hand side first:

$4\cdot 45 + 3r = 180+3r$

So, the equation is

$180+3r =336$

Subtract 180 from both sides:

$3r = 336-180 = 156$

Finally, divide both sides by 3:

$r = \dfrac{156}{3} = 52$