Question

2x-5y=7

Answer 1

I'm in eight grade and need help with solving this problem using the elimination method

Thanks,
Allibeaver

Answer 2

I need to figure out what y and x are!

Here is the entire question:
Jonah is solving the following systems of equations.
2x-5y=7
-2x+4y=-5
Explain how Jonah could use the elimination method to solve the system of equations.
Give the solution.

That's the entire question, but I know how to do it and explain how to do it but I just can't get all the numbers to connectr in my head or on the paper!

Plz help, I've been stuck on the question for at least an hour!!

Thanks!

Answer 3

oh, well first you chose x or y to eliminate

Answer 4

since, x is easier, lets start with x

Answer 5

2x and -2x= to 0, so you can cross out the 2x's

Answer 6

now you have -5y=7
4y=-5, so you can subtract the y's so got -1 y= to 2 (cause 7-5=2_

Answer 7

oh sorry that _ in front of the 2 is suppose to be a )

Answer 8

well you can't a - in (-y=2, (and you should know that there's an invisible one in front of the negative), so you have to divide the -1 to both sides, and 2 divided by -1 would equal to -2

Answer 9

NOW, Y=-2

Answer 10

after that you plug in that into the equation to get x (you can chose the first equation, 2x-5y=7 or the second, -2x+4y=-5, the answer will be the same).

Answer 11

So, lets say you chose the first equation, it would look like,
2x-5(-2)=7
then, 2x-10=7

Answer 12

add -10 to 7, so it would be 2x=17

Answer 13

then you divide 2 to both sides and X WOULD EQUAL TO 8.5

Answer 14

thus, y= -2 (and)
x=8.5

Answer 15

(unless I did the math wrong)

Answer 16

I THINK ITS WRONG BECAUSE -5(-2)=10

NOT -10

Answer 17

SO THE EQUATION IS 2X+10=7

Answer 18

2X=7-10
X=-1/2

Answer 19

your right it does equal 10

Answer 20

NOW WE CAN CHECK IT BY APPLYING X AND Y VALUE IN THE SECOND EQUATION

Answer 21

IT WILL LOOK LIKE -2(-1/2)+4(-2)=-5

Answer 22

BUT WE ARE NOT GETTING THE CORRECT ANSWER BECAUSE WE R GETTING -7=-5
SO ITS WRONG IF WE GET -5=-5 THEN ITS RIGHT

Answer 23

what im really confused on what you just said