Question

what is the solution to the following system? -3x-2y=-12?..........
i need help fast,Please and thank you.Also an explanation on how you solved it would be much appreciated :)

Answer 1

Is there more to the system than just that?

Answer 2

oh gosh ,im so sorry.... the whole thing 9y+6x=-9 , -3x-2y=-12. @PlatypusFeet

Answer 3

get y alone in each equation and then set them equal to eachother

Answer 4

how would you do that? @Costanza

Answer 5

Alright, let's try solving this using substitution.

First let's take the second equation -3x-2y=-12 and get y by itself.

-2y=3x-12
y=(-3/2)x+6

Now since we know what y is, we can plug it into the other equation.

9((-3/2)x+6)+6x=-9
Simplifies to -
(-27/2)x+54+6x=-9
(-15/2)x=-63
x=8.4

To find y just plug x back into an equation.

-3(8.4)-2y=-12
Simplifies to-
y = -6.6

So x = 8.4 and y = -6.6

Just plug these back in to check and see if they're correct.

9(-6.6)+6(8.4)=-9 -> -59.4+50.4=-9 -> -9=-9
-3(8.4)-2(-6.6)=-12 -> -25.2 + 13.2 = -12 -> -12=-12

Answer 6

\[9y+6x=-9 \\ -3x-2y=-12\] multiply the second one by \(3\) and you get
\[9y+6x=-9 \\-9x-6y=-36\]

Answer 7

add and you get \(0=-45\) which means the lines are parallel and do not intersect

Answer 8

you can kind of see they are parallel from the start since the ratio of the coefficients are the same

Answer 9

satellite you can't cancel out 6x with -6y

Answer 10

maybe i read it wrong

Answer 11

you can do it your way if you multiply the second one by 2 to get
9y+6x=-9
-6x-4y=-24

Answer 12

oooh i made a mistake, sorry

Answer 13

then 5y=-33 y=-6.6

Answer 14

yeah lol its okay

Answer 15

Thank you so much to all of you!!

Answer 16

\[6x+9y=-9 \\-6x-4y=-24\]

Answer 17

The elimination method would be faster had I been thinking.

Answer 18

but wait... so my answer choices were 2,1, -2,-1 i infinate solutions and no solutions...

Answer 19

does this mean it would be infinate?

Answer 20

those are the only options?

Answer 21

yes

Answer 22

@PlatypusFeet @satellite73

Answer 23

The answer shouldn't be any of those. Is it possible the equations were written down wrong earlier?

Answer 24

idk what to say. It's not 2,1 -2,-1 or no solutions cause we found a solution but i dont think there are an infinite amount of solutions

Answer 25

Infinite solutions would mean that you can plug any number into the equations and it would work.

Answer 26

9y+6x=-9 , -3x-2y=-12 Those were the two equations.. it says solve by elimination? i probably should've mentioned that .so sorry

Answer 27

@PlatypusFeet , @Costanza , @satellite73

Answer 28

elimination is the method that satellite and i used earlier

Answer 29

To solve through elimination you would multiply the second equation by 2:
-6x-4y=-24
Add with first equation:

6x+9y=-9
-6x-4y=-24

You should get 5y=-33, which means y is equal to -6.6

Solving through elimination doesn't change the answer.

Answer 30

Oh okay good..Thats whats confusing me though,these damned answer choices..let me double check to make sure i got this equation right...

Answer 31

alright im sorry im an idiot. i put 9y+6x=-9 , -3x-2y=-12 .... it should be
-3x-2y=-12.....9x+6y=-9
@PlatypusFeet @Costanza

Answer 32

that's alot easier lol

Answer 33

Then its no solution.

Answer 34

i accidently switched the x & ys while retyping..sorry about that lol..

Answer 35

no solution? alrite thank you guys so much!!! such a big help :)

Answer 36

@satellite73 explained it earlier why they cancel each other out, making 0 = -45, which is a false answer. This makes it no solution.

Answer 37

oh okay i see.... um.. care to help with one more equation?

Answer 38

sure

Answer 39

x-y=11 ****-x+y=-11 ?

Answer 40

3,4
-3,-4
no solutions
infinite solutions

Answer 41

I believe that would be infinite solutions.

x-y=11
-x+y=-11

Added together gets:
0=0

Meaning any answer could work.

Answer 42

Your a life saver... thankyou again..