Solve the simultaneous equations.
x + 2y = 9
5x – y = – 10

(- 1, 5 )

Step-by-step explanation:

Given the 2 equations

x + 2y = 9 → (1)

5x - y = - 10 → (2)

Multiplying (2) by 2 and adding to (1) will eliminate the y- term

10x - 2y = - 20 → (3)

Add (1) and (3) term by term to eliminate y

11x + 0 = - 11

11x = - 11 ( divide both sides by 11 )

x = - 1

Substitute x = - 1 into either of the 2 equations and solve for y

Substituting into (1)

- 1 + 2y = 9 ( add 1 to both sides )

2y = 10 ( divide both sides by 2 )

y = 5

solution is (- 1, 5 )

x + 2y = 9 x + 2y = 9

》

5x - y = - 10 (×2) 10x - 2y = - 20

+

11x + 0 = - 11

11x = - 11

x = - 1

Thus :

- 1 + 2y = 9

Add both sides 1

2y - 1 + 1 = 9 + 1

2y = 10

Divide both sides by 2

2y ÷ 2 = 10 ÷ 2

y = 5

a and c

step-by-step explanation: