Question

Solve using elimination:
-9x = -4y − 10
-11x + 5y = -13

Answer 1

@mathstudent55

Answer 2

@mathstudent55

Answer 3

First, write both equations in the form
\(ax + by = c\)
The second is already in that form.

Answer 4

so it -9x+-4y=-10

Answer 5

No.
You need to add 4y to both sides:

-9x = -4y − 10
+4y +4y
--------------------add
-9x + 4y = -10

Now write one above the other.

Answer 6

ok i did that now what do i do

Answer 7

@mathstudent55

Answer 8

Now we have this.

-9x + 4y = -10
-11x + 5y = -13

Answer 9

yes and i got this -20x+9y=-23

Answer 10

Now we need to find which variable to eliminate.
Since by simply adding the equations neither variable gets eliminated, we need to do what we did last time. We have to multiply both equations by numbers that will make one variable add to zero.

Answer 11

As you can see, neither variable was eliminated when you added the equations.

Answer 12

ok so what do i multiply the first equestion by

Answer 13

-9x + 4y = -10
-11x + 5y = -13

Look at the y terms.
If you multiply the first equation by -5, you get -20y.
If you multiply the second equation by 4, you get 20y.
-20y and 20y add up to zero.
That would eliminate the y variable, just what we need.

Answer 14

then do i add them to elimanate them

Answer 15

Yes, but first multiply them by the numbers.

Answer 16

x=-2

Answer 17

the answers are x=-2 y=-7

Answer 18

45x - 20y = 50
-44x + 20y = -52
--------------------add
x = -2

You are correct.

Now insert -2 for x in one of the original equations, and solve for y.

Answer 19

i got it ima try the next one on my own and if i need your help i'll ask you if that ok

Answer 20

What did you get for y?

Answer 21

-9x = -4y − 10
-9(-2) = -4y - 10
18 = -4y - 10
28 = -4y
y = -7

Answer 22

i got -7

Answer 23

Great.

Answer 24

can you help me on one i just posted