Question

Guys I Seriously Don't Get This Please Help!!

-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.
Part B: Show that the equivalent system has the same solution as the original system of equations.

Answer 1

Meadling too!!

Answer 2

Easy!! multiply the top eaquasion by -3, so you get 9x-21y=48, and -9x+5y=16. then cancel out the X to get -16y=64 then solve for Y

Answer 3

how would you create a equivalent equation?

Answer 4

Do you know this subject material/ Do you know what an Equivalent Equation is??

Answer 5

yes

Answer 6

sortof

Answer 7

So then tell me what you think you need to do to find the Equivalent Equations

Answer 8

umm write an equation that is equal to the first equation ? idk

Answer 9

you do the same thing to find X and then you plug in the number to find the solution. The solutions should be Equivalent. Thats your answer. Tell me what you get for X and we will go from there

Answer 10

the first one?

Answer 11

wait what?? Can you just tell me the answer lol

Answer 12

multiply the top equation by -5 and the bottom by 7 to cancel out the Y.
Tell me what you get for the new equations

Answer 13

this is prolly so wrong but i got
15x=80
-63x=112

Answer 14

then combine

Answer 15

tell me whatcha get

Answer 16

are those right?

Answer 17

wait but how do you combine them

Answer 18

you do 15 -63 to get -48X=192, then X=-4

Answer 19

and what did you get for Y=_??

Answer 20

what does x equal again?

Answer 21

wait im totally confused @Da_Homie

Answer 22

X= -4

Answer 23

do the same thing to get Y

Answer 24

or just plug in X and solve for Y

Answer 25

once you get Y then we can solve the problem

Answer 26

Tell me whatcha get fir Y

Answer 27

x=-4 for both equations?

Answer 28

yep, plug it in and solve for Y

Answer 29

Plug it into both equations so we can see if you got X=-4 correct

Answer 30

for the first one i got y=-2

Answer 31

ok, now do the same for the next, and if you get Y=-2 also then X is correct

Answer 32

i got y=-4

Answer 33

so your X is wrong then...
Your gonna need to redo X

Answer 34

how do we do that

Answer 35

multiply the top equation by 5

Answer 36

multiply the bottom equation by -7

Answer 37

what would that be then?

Answer 38

-15X+35Y=80

Answer 39

49X-35Y=-112

Answer 40

Ys now cancel out

Answer 41

so -15x=80 and 49x=-112

Answer 42

yes

Answer 43

soo what now

Answer 44

darn...the X comes out to a decimal. Lets start with Y lol

Answer 45

jus hold on ill figure it out for u

Answer 46

yay

Answer 47

lol

Answer 48

Your sure these are the right numbers????

Answer 49

yes i copy and pasted it lol

Answer 50

well... both of our numbers are gonna be decimals :(... that means our job is gonna get confusing

Answer 51

oh :(

Answer 52

unless were doing it wrong...?

Answer 53

i dunno... everything comes to a decimal :(

Answer 54

one of my friends might know @SolomonZelman

Answer 55

you would have to wait for him to get online tho

Answer 56

ok thats fine

Answer 57

srry bud

Answer 58

its ok i hate this test

Answer 59

lol i getcha, same

Answer 60

could you help me with another problem tho?

Answer 61

x + 2y < -5
x - y > 0

Describe the steps to graph the solution set to the system of inequalities.

Answer 62

on a number line right?

Answer 63

no on a graph ...

Answer 64

oh yes, i think i remember these, with the shading right??

Answer 65

yess

Answer 66

have you done these before

Answer 67

no ..

Answer 68

darn

Answer 69

i havent in a long time

Answer 70

:// crapp

Answer 71

we might be able to figure it out tho, do you know somewhat what you are doing??

Answer 72

yeah i think you have to solve for y first

Answer 73

then figure out the solutions

Answer 74

wait no scratch the first part your supposed to find the solutions first

Answer 75

do you know how to go about doing that???

Answer 76

i think its the same way you were trying to to do with this problem ^

Answer 77

ok so lets do it

Answer 78

okayy

Answer 79

do multiplly the bottom by 2 and cancel out the Y

Answer 80

no you solve for y first

Answer 81

i think

Answer 82

then solve for Y lol

Answer 83

thats what im doing lol

Answer 84

oh lol

Answer 85

wait lol do you subtract x from both sides ?

Answer 86

multiply the bottom by -1, then the Xs will cancel out

Answer 87

what do you mean multiply the bottom??

Answer 88

the bottom equation needs to be multiplied by -1 so the Xs can cancel out

Answer 89

multiply what?

Answer 90

THE BOTTOM EQUATION lol

Answer 91

NO multiply WHAT on the bottom equation?

Answer 92

the whole equation

X and Y are multiplied by -1

Answer 93

like this -1( -9x+5y=16)

Answer 94

BOTTOM

Answer 95

that is the top

Answer 96

that is the bottom one

Answer 97

but it really doesnt matter, so that'l work ;)

Answer 98

but that just increases everything