Answer:
4
Step-by-step explanation:
y = 4x + 5
Equating it with
y = mx + b
m = 4
13x + 7 + 4x + 15 = 90
17x + 22 = 90
17x = 68
x = 4
4(4) + 15= 16 + 15= 31
13(4) + 7 = 52 + 7 = 59