Question

Solve the following simultaneous equation.

5x + 2y = –3; x + 5y = 4

Answer 1

5x + 2y = −3     ...(1)

x + 5y = 4     ...(2)

x + 5y = 4 ⇒ x = 4 − 5y

5(4 − 5y) + 2y = −3

20 − 25y + 2y = −3

20 − 23y = −3

−23y = −3 − 20

−23y = −23

y = 1

x + 5(1) = 4

x + 5 = 4

x = −1

x = −1, y = 1