Tolong di jawab buwat besok

A. 5x-30 = 2x+15
5x-2x = 15+30
3x = 45
x= 45/3
x= 15

b. (4y+25)+(4y-5)= 180
8y-20 = 180
8y = 200
y= 200/8
y= 25