System of equations, 1 problem, please help?

Question

4x - 3y = 30 
2x + y = 30

Answer 1

Substitution method :

The system of equations are 4x - 3y = 30 and 2x + y = 30.

solve 2x + y = 30 for y ,Since the coefficient of y is 1.

y = 30 - 2x.

Substitute y = 30 - 2x in 4x - 3y = 30 , and solve for x.

4x - 3(30 - 2x) = 30

4x - 90 + 6x = 30

10x - 90 = 30

10x = 30 + 90

10x = 120

→ x = 120/10 = 12.

Substitute the value x = 12 in y = 30 - 2x, and solve for y.

y = 30 - 2(12)

y = 30 - 24

→ y = 6.

Therefore, solution of the system (x, y) = (12, 6).