Question

How to solve systems with elimination?
5x - 2y = 28
-20x + 8y = -100

I know that if there are two of the same variable then they cancel and then it is easy to solve when you add the equations together, but what if neither equation has corresponding variables???

Answer 1

you have to make them become corresponding

5x-2y= 28 (multiply by 8 ) = 80x-16y =224

Answer 2

How are those corresponding :s

Answer 3

and you have to make this for the second one

-20x +8y=-100 (muliply by 2) = -40x +16y = -200



and solve by elimination now

Answer 4

eliminate 16y

Answer 5

why did you multoply by 8 and 2 sorry

Answer 6

If I was given that problem I would eliminate x... seems easier if I distribute the 4 all over the first equation

Answer 7

and for that reason. I have to distribute the 4 all over the first equation because I want to eliminate a variable and solve for the other. In this case,

4(5x-2y=28)

20x-8y=112 (this is my new first equation)

so I add my new first equation to the second equation so I can get rid of the x

Answer 8

to make them corresponding...

Answer 9

@Michele_Laino please help

Answer 10

i got 3/5...

Answer 11

oh geez we are forced to take the y's out and then solve for x

because by distributing the 4 all over the first equation, I ended up destroying x and y., and we don't want that.

Answer 12

\[8(5x-2y=28)\]
\[2(-20x+8y=-100)\]

\[40x-16y=224\]
\[-40x+16y=-200\]

HUH? Am I reading this wrong? even I got the same problem.

Answer 13

i was right @icalibear

Answer 14

i meant to type 40x

Answer 15

sorry! typo

Answer 16

i will fix this

Answer 17

we are supposed to distribute 8 and 2 THROUGHOUT THE equation. We can't have it one sided