Math help? Use substitution to solve the linear system.

Question

4. 4x + 3y = 31, y=2x+7

5. -12x + y = 15 ,3x+2y=3

6.) x+1/2y=7 ,3x+2y=18 

Answer 1

(4)

The equations are and .

Substitute in .

Substitute in .

Therefore, the solutions are and .

Answer 2

(5)

The equations are and .

Consider the equation .

Solve for .

Substitute in .

Substitute in .

Therefore, the solutions are and .

Answer 3

(6)

The equations are  and .

Consider the equation .

Solve for .

Substitute  in .

Substitute  in .

Therefore, the solutions are  and .