Max practices the piano in the guitar for a total of 150 minutes every day he practices guitar 80 minutes more than he practices the piano how much time does max been practicing the piano every day

Eg. x minutes for piano practice, y minutes for guitar practice

The equation
x + y = 150 (1st equation)
y = 80 + x (2nd equation)

How to solve
change y to 80 + x in 1st equation
x + y = 150
x + 80 + x = 150
2x + 80 = 150
2x = 150 - 80
2x = 70
x = 70/2
x = 35

Max practice the piano 35 minutes everyday