Question

−6x+ y =20
−3x−3y =−18
can anybody explain how to do substitution?

Answer 1

solve the first equation for y

−6x+ y =20

y =20 + 6x

Then plug this into the second equation

−3x−3y =−18

−3x−3(20+6x) =−18

-3x - 60 - 18x = -18

then solve for x

Answer 2

use the solution for x to find the solution for y

Answer 3

but shouldnt i end up with an answer for X & Y?

Answer 4

yes, what did you get when you solved -3x - 60 - 18x = -18 for x

Answer 5

-3, is that correct? & then I plug in that to either one of the equations to get y?

Answer 6

no that's not correct

Answer 7

?

Answer 8

-3x - 60 - 18x = -18

-21x - 60 = -18

-21x = -18+60

-21x = 42

x = 42/(-21)

x = -2

Answer 9

ohhhhh, i see!

Answer 10

now use this to find y

Answer 11

thank you!