Question

Find a solution to the following system of equations.
-3x+3y = -9
-3x + y = 7

Answer 1

(–5, –8)
(5, 2)
(–2, 2)
(0, 7)

Answer 2

@texaschic101

Answer 3

the first course of action here is to eliminate a variable.....either x or y, it does not matter.
I believe it would be easier to eliminate the x's.

-3x + 3y = -9 -- multiply everything by -1
-3x + y = 7
-----------
3x - 3y = 9 (result of multiplying by -1)
-3x + y = 7
-----------add
-2y = 16 -- divide by -2
y = -8

then sub -8 back in for y in either of the original equations to find x
do you have any questions about what I just did ?

Answer 4

now if you wanted to eliminate the y's instead of the x's, you would have multiplied the second equation by -3.....then added the equations together. But either way, you should arrive at the same answer.

Answer 5

27?

Answer 6

or 24?

Answer 7

@texaschic101

Answer 8

@LegendarySadist can u help?

Answer 9

Just sub y=8 back into -3x + y = 7 and solve for x.

Answer 10

Whoops, that would be y=-8

Answer 11

so -11?

Answer 12

@LegendarySadist

Answer 13

@jim_thompson5910

Answer 14

hopefully you understand how y = -8

what you do from here is replace every copy of 'y' in an equation like -3x + y = 7 and solve for x


-3x + y = 7

-3x + (-8) = 7 ... replace y with -8

-3x - 8 = 7

-3x - 8+8 = 7+8 ... Add 8 to both sides.

-3x + 0 = 15

-3x = 15

-3x/(-3) = 15/(-3) ... Divide both sides by -3 to fully isolate x.

1x/1 = -5

1x = -5

x = -5

Answer 15

So together, x = -5 and y = -8 forming the ordered pair (-5,-8)

if you were to graph the two lines, the point (-5,-8) would be on both lines. It is the point of intersection between the two lines

Answer 16

Yes I understand and oh okay thank you

Answer 17

ok great