Question

slove this 2x+3y=21 3x-6y=-24 slove this with substution method

Answer 1

2x + 3y = 21
-3x - 6y = -24

Solve the second equation for x

-3x - 6y = -24
-3x = -24 + 6y

Divide every term by -3

x = 8 - 2y

Substitute (8-2y) for x in the OTHER (first) equation

2x + 3y = 21

2(8-2y) + 3y = 21

16-4y + 3y = 21

16 - y = 21
-y = 5
y = -5

Substitute -5 for y in x = 8-2y

x = 8 - 2y
x = 8 - 2(-5)
x = 8 + 10
x = 18

So the solution is (x, y) = (18, -5)