Question

​−8x+4y=24 ​−7x+7y=28 ​​ What is the solution?

Answer 1

​−8x + 4y = 24 -- (1)
​−7x + 7y = 28 -- (2)

Eqn (1) & (2) are simplified as

y - 2x = 6 -- (3)
y - x = 4 -- (4)

By making y the subject of formula in (4), we have

y = x + 4 -- (5)

Substitute x + 4 for y in (3), then

x + 4 - 2x = 6
x - 2x = 6 - 4
- x = 2
x = - 2.

Substitute - 2 for x in (5), then

y = - 2 + 4
y = 2.

Therefore, (x, y) = (- 2, 2) ...Ans.