X-3y-7=0 , 3x-3y-15=0 solve this using cross multiplication

Question

asked Jul 17, 2022 170k views

1 Answer

Droidd · Answer 1 · 2022-07-22T09:42:13+0000

Answer:

x = 4 , y = -1

Explanation:

x - 3y = 7 -- (1)

3x - 3y = 15 -- (2)

Rewriting (1), x = 3y + 7 -- (1)'

Substituting (1)' into (2),

3 ( 3y + 7 ) - 3y = 15

9y + 21 - 3y = 15

6y = -6

y = -1 -- (3)

Substituting (3) into (1),

x - 3 ( - 1 ) = 7

x + 3 = 7

x = 4 -- (4)

According to (3) and (4),

x = 4 , y = -1