Question

What is the x coordinate of the solution of the system? 2x+y=15 and x-y=3

Answer 1

x - y = 3

x = 3 + y

x -3 = y

y = x-3

put it in 1st equation

2x +y = 15

2x + x - 3 = 15

3x - 3 = 15

3x = 15+3 = 18

x = 18/3 = 6

x = 6