Question

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Answer 1

if you multiplied everything in equation 1 by 5, you would get

-x+2y=-21

5*(-x+2y)=5*(-21)

-5x + 10y = -105

Answer 2

we have this equivalent system

-5x + 10y = -105
5x + 8y = -3

Answer 3

what happens when we add the two equations?

Answer 4

18y = 108? then divide by 18 ?

Answer 5

it should be 18y = -108, but you have the right idea

Answer 6

oh okay! I think I understand now :)

Answer 7

you would divide both sides by 18 to get

18y = -108

y = -108/18

y = -6

Answer 8

then you use this value of y and plug it into any equation with x,y in it

from there you solve for x

Answer 9

thanks !
im confused on one more though

Answer 10

whats that

Answer 11

-4x-3y=9
5x + 8y = 10

Answer 12

which variable would you like to eliminate?

Answer 13

-4x-3y=9

Answer 14

that's an equation

Answer 15

which variable? x or y?

Answer 16

x

Answer 17

notice how -4x + 5x = 1x which isn't 0x or 0 like we want

Answer 18

if we had -4x + 4x or -5x + 5x, they would add to 0 and it'd go away

Answer 19

so what can we do to fix this?

Answer 20

eliminate the y ?

Answer 21

I tried multiplying 5 and -4 but it doesn't work

Answer 22

what do you mean

Answer 23

5*(-4x-3y=9)
-4*(5x=8y=10

Answer 24

ok multiply everything in equation 1 by 5 to get what?

Answer 25

oh I got that one

Answer 26

never mind

Answer 27

ok I'm glad you figured it out

Answer 28

wait im confused it doesn't make sense

Answer 29

ok multiplying everything in equation 1 by 5 gives you

5*(-4x-3y)=-5*(9)

-20x - 15y = -45

Answer 30

oh I got that

Answer 31

multiplying everything in equation 2 by 4 gives you

4*(5x + 8y) = 4(10)

20x + 32y = 40

Answer 32

we have this new system

-20x - 15y = -45
20x + 32y = 40

Answer 33

oh my math was wrong

Answer 34

is this one no solution?

Answer 35

why do you say that

Answer 36

because -15+32 = 17 and you cant divide it by 5

Answer 37

17y = -5 so y = -5/17 (divide both sides by 17)

Answer 38

then use this to find x

Answer 39

its not right lol I don't know what im doing wrong

Answer 40

the original system is

-4x-3y=9
5x + 8y = 10

right?

Answer 41

yes but when I plug in x and y into the original system it doesn't = 9

Answer 42

oh I made an error

Answer 43

5*(-4x-3y)= 5*(9)

-20x - 15y = 45

Answer 44

so the system should be

-20x - 15y = 45
20x + 32y = 40

Answer 45

okay yay ! I knew something was wrong thank you so much

Answer 46

you're welcome