Question

A system of equations is shown below:

-3x + 7y = -16
-9x + 5y = 16

Part A: Create an equivalent system of equations by replacing one equation with the sum of that equation and a multiple of the other. Show the steps to do this. (6 points)

Part B: Show that the equivalent system has the same solution as the original system of equations. (4 points)
@itsbribro @sammixboo @thomaster

Answer 1

im sorry i dont know

Answer 2

@dan815 @camerondoherty @Nnesha

Answer 3

@linn99123

Answer 4

@Skyz @KlOwNlOvE

Answer 5

I think it is asking for elimination multipply the first equation by -3 let me know what you get

Answer 6

-3(-3x + 7y = -16)

Answer 7

i dont know what you mean. like plug -3 into x and y?

Answer 8

naw just multiply it by everything

Answer 9

9x+(-21)y=48

Answer 10

okay and that negative will be negative
9x-21y=48
-9x+5y=16
now combine like terms
by=c

Answer 11

what?

Answer 12

combine like terms with the 2 equations

Answer 13

-16y=64

Answer 14

then y=-4

Answer 15

okay now divide 64 by -16

Answer 16

yes now substitute -4 in for y in one of those equations

Answer 17

-9x+(-20)=16

Answer 18

now what

Answer 19

-9x-20=16
now solve for x

Answer 20

x=-4

Answer 21

@KlOwNlOvE now what

Answer 22

okay so x=-4 and y=-4

Answer 23

yes

Answer 24

okay so show how -9x-20=16 is equivalent to -9+5y=16

Answer 25

you mean -9x correct?

Answer 26

@camerondoherty @satellite73 can one of yall help him have a feeling i did it the wrong way and gtg

Answer 27

yes

Answer 28

idk how they are equivalent

Answer 29

I'm sure i led you in the wrong direction hopefully one of them will come help not real sure might have to substitute

Answer 30

they normally dont but okay.

Answer 31

i dougbt they will join

Answer 32

how do i do Part B: Ranga helped me on part a

Answer 33

Part A: -3x + 7y = -16
-9x + 5y = 16

Let us replace (2) by adding (2) to two times (1):
2 times (1): -6x + 14y = -32
Add (2): -9x + 5y = 16
--------------------
-15x + 19y = -16

So the second pair of equations are:
-3x + 7y = -16
-15x + 19y = -16

Answer 34

okay now do what we did to the other system

Answer 35

what do you mean find x and y?