(2*x + 5) * 3 = 15

2*x+5=15:32*x+5=5

2*x=5-5

2*x=0

x=0:2

x=0

(49-11*x):3=9

49-11*x=9*3

49-11*x=27

11*x= 49-27

11*x=22

x=22:11

x=2