Question

3x+(2x+5)+(2x+10)+(2x-15)=360

Answer 1

Collect all x terms and all numbers. Ignore the brackets if they are confusing you since it makes no difference in this question if they exist or not since it's only addition and subtraction operations.

9x = 360

Divide both sides by 9.

x = 40.

Answer 2

$\bf 3x+(2x+5)+(2x+10)+(2x-15)=360 \\\\\\\\3x+2x+2x+2x+10+5-15=360\implies 9x+0=360\\\\\\\\x=\cfrac{360}{9}\implies x=40$