Question

Solve the system of linear equations by substitution. x−y=5 x+3y=9

Answer 1

`y = x - 5`

Substitute y in the x+3y=9

`x + 3(x - 5) = 9 \\ x + 3x - 15 = 9 \\ 4x = 9 + 15 \\ 4x = 24 \\ x = 6`

Substitute x = 6 in any given equations. I will choose to substitute in y = x-5

`y = x - 5 \\ y = 6 - 5 \\ y = 1`

The answer is (6,1)