Question

Which equation results from adding the equations in this system?x + 6y = 9-x+2y = - 158y = -68y = 64y = 244y = - 6

Answer 1

Given that

x + 6y = 9---------1

and

-x + 2y = - 15------- 2

Make x subject of formula in both equations

From equation 1

x = 9 - 6y

From equation 2

2y = -15 + x

2y + 15 = x

x = 2y + 15

Equating the two equations

2y + 15 = 9 - 6y

collect like terms

2y + 6y = 9 - 15

8y = -6