Question

What is the solution for the system of equations?

Use the substitution method to solve.

2x+y=20−5 y=−6x+12

Answer 1

@3mar

Answer 2

Well, I am here.

That is a nice question and easy at the same time!

Answer 3

wait its 2x+y=20 -5y= -6x+12

Answer 4

We can use substitution method to plug one equation into the other one!

Answer 5

To do so:
- solve for one variable (say y) in one equation.
- plug this equation into the other equation.

Can you show me how do you understand it?

Answer 6

OH

Answer 7

i get that but i didnt give me anything to plug in

Answer 8

Can you share your works/steps, please?

Answer 9

ok

Answer 10

ok so 2*-6+-5 = 20 ? right

Answer 11

It would better to show me how you did the math, @gigi1103

Answer 12

ok i was just making sure i set it up right

Answer 13

Ok, Take your time.

Answer 14

so 2* - 6 = -12 + -5 = -17

Answer 15

so thats not right is it?

Answer 16

You started with which equation?

Answer 17

the first one

Answer 18

2x+y=20-5

Answer 19

Great!
So you solved for y?

Answer 20

OH

Answer 21

yea ill do the other one now

Answer 22

wait

Answer 23

when you solved the first equation for y, what you got?

Answer 24

-17

Answer 25

You did not get me!

what I mean is:
\[2x+y=20\]
\[2x+y-2x=20-2x\]
\[y=20-2x\]

that is what we need!
got it??

Answer 26

OH subtracting from both sides

Answer 27

In other words, 3mar has solved 2x+y=20 for y. This is what you have to do. Substituting (20-2x) for y in the other equation will now elimiinate y; you end up with an equation in x only.

Answer 28

\(\Large y=20-2x\)
this is what we will plug it into the other equation!

Answer 29

so for the other one

Answer 30

Yes, to have y in one side "alone" and the other terms in the other side!

Answer 31

Just replace \(y\) in the other equation with this equation [\(\Large y=20-2x\)]

Answer 32

wait im confused

Answer 33

do i plug in the 2x next to the -6

Answer 34

I will simplify it for you!