Question

Please helppppppp triple sad face!!!!

Elimination method.

5x + 2y = 55
2x - y = 19

answer is x+y=12 ...... I need to know why

Answer 1

Let Me Guess, You Are HomeschooleD?

Answer 2

So Aisha, The Elimination method is all about trying to eliminate a variable in one of the equations so we can find the other. So

Answer 3

i kno how to do the elimination method but this is a trick question

Answer 4

by observing the equations we can see that by multiplying the 2nd equation by 2 we get 2(2x-y)=2*19; 4x-2y=38, now note the relation between the third equation that we got and the first one. In the first one we have +2y and in the third we have -2y

Answer 5

but why is the answer x+y=12

Answer 6

now add the third equation to the first we get 5x+2y\[5x+2y+(4x-2y)=55+(38)\] thus 9x=93, so x=93/9, now we plug in x=93/9 in equation 2 we get y=186/9-19=15/9
now x+y=108/9=12

Answer 7

wheres the y=186/9-19=15/9
come from?

Answer 8

@Xesevoli

Answer 9

@yomamabf

Answer 10

we got x=93/9 right?

Answer 11

yea

Answer 12

plug it in 2x-y=19

Answer 13

i got something really weird i dont know where u came across 12

Answer 14

you agree that x=93/9?

Answer 15

yea

Answer 16

ok \[2*(93/9)-y=19\]
\[186/9-y=(19*9)/9=171/9\]

Answer 17

whered the 186 come from?

Answer 18

\[2*x=2*93/9=(2*93)/9\]

Answer 19

wait what? whered that 2 come from??????

Answer 20

wouldnt it be 4(93/9)

Answer 21

we plugged in x=93/9 in 2x - y = 19

Answer 22

okay gotcha

Answer 23

yeah!

Answer 24

and then what

Answer 25

by solving for y, you get y=15/9

Answer 26

yea

Answer 27

x+y=93/9+15/9=108/9=(12*9)/9=12

Answer 28

isnt it -15/9?

Answer 29

-y=-15/9, so y=15/9

Answer 30

oh okay gotcha

Answer 31

sorry im slow so where does the 108 come from

Answer 32

x+y=93/9+15/9=(93+15)/9=108/9=(12*9)/9=12

Answer 33

why do u multiply 12 times 9?

Answer 34

108=12*9 so when we divide by 9 only 12 is left

Answer 35

im still lost as to where you got that 108 from

Answer 36

ok i figured it out but where di the 12 come from