Question

Solve the following system of equations.
8x-7y=-21
-3x-5y=-15
x=?
y=?

Answer 1

make in your equation appear 3x ...how will you do that?

Answer 2

first*

Answer 3

3x(8x-7y=-21) ?

Answer 4

you mean multiply both sides by 3x?

Answer 5

yea

Answer 6

then you will have 24x...you want that?

Answer 7

i dont know!

Answer 8

if i knew the answer, i wouldnt be asking the question..

Answer 9

why would I want 3x to appear in the 1st equation?

Answer 10

if you find that ..you will understand whole problem

Answer 11

you told me to put 3x in the equation so thats what i did.. why is that wrong now?

Answer 12

no..not put 3x in the 1st equation...you need to make 3x appear in the 1st equation...what is the little trick that will make the 1st equation have 3x instead of 8x?

Answer 13

wouldnt it be easier to just make both equations have 24x?

Answer 14

thats okay and it is correct

Answer 15

so how can u make both equations have 24x?

Answer 16

multipy the top by 3 and the bottom by -8. 24x-21y=-61 and 24x+40y=120

Answer 17

one small mistake there 21*3=63 not 61

Answer 18

ok

Answer 19

now you have 24x in both of your equations

Answer 20

yes. now what

Answer 21

solve the 1st equation for 24x and then put it in your 2nd equation

Answer 22

idk how. i moved 21y over. and made it 24x=-63+21y and then tried to divide by 24 but it doesnt work out

Answer 23

no you dont need to divide this ...you need this!

Answer 24

put the right hand part of this equation on your 2nd equation

Answer 25

what?

Answer 26

your 2nd equation is 24x+40y=120 right?

Answer 27

yes

Answer 28

in that 2nd equation where you see 24x put what you found before from the first

Answer 29

i didnt find anything from the first..?

Answer 30

all i have from the first is 24x=-63+21y

Answer 31

what you need is to get rid of x so you can have an equation with only y as unknown

Answer 32

you have 24x from the first:)

Answer 33

doesnt matter now. my page with the question timed out.

Answer 34

what do you mean?you dont need to solve that anymore?

Answer 35

nope. we took to long.

Answer 36

look...from the first equation you have -63+21y=24x from the 2nd you have 24x+40y=120...so the 2nd equation becomes -63+21y+40y=120 solve that to find y

Answer 37

61y=183--->y=183/61 calculator and get your result

Answer 38

y=3