Question

Solve the following system of equations:

-2x + y = 1
-4x + y = -1

Answer 1

(3, 1)
(-1, 3)
(-1, -3)
(1, 3)

Answer 2

There are two methods for solving a system of linear equations. Elimination and Substitution. Which one do you think we should perform?

Answer 3

y =1 + 2x
put this equation in 2nd eq. and
solve for x
then use that value of x in first eq. to get the value of y

Answer 4

what

Answer 5

-2x + y = 1
-4x + y = -1

Okay, so we're going to solve by elimination. First, what do we need to multiply either of the two equations by in order to get the x terms to cancel each other?

Answer 6

um

Answer 7

-2x + y = 1
-4x + y = -1

If we multiply the first equation by -2, it will cancel. As shown

-2(-2x + y = 1)
-4x + y = -1

4x + y = 1
-4x + y = -1

Now you can add both the equations together, and the x terms should cancel. Then you can solve for y. Once you have y, plug it into either equation and solve for x. This will give you your final solution.

Answer 8

y=1
y=-1
thats after the x is canceled right but i dont know what i do with that

Answer 9

Simply add both of them together

4x + -4x + y + y = 1 + -1

Did you see what I did? Just simply adding both equations together.

You'll notice the x terms will cancel. And we have

2y = 0

Now divide 2 by 0 .

Answer 10

0

Answer 11

Right. So when y = 0, we are done. There are No Solutions.
When 0 = 0, there are infinite solutions.

The more you do System of Equations, the more you'll get it. Want to do some practice problems? Do you have any similar problems?

Answer 12

i have similar problems and thanks im kinda getting the hang of it but i think i should do more of them too

Answer 13

Okay. Go ahead and post and I'll help you here. No need to make a new question. I don't care about medals or anything.

Answer 14

wait for the last question none of the choices were no solutions

Answer 15

What are they.

Answer 16

(3, 1)
(-1, 3)
(-1, -3)
(1, 3)

Answer 17

(3, 1)
(-1, 3)
(-1, -3)
(1, 3)

Answer 18

-2x + y = 1
-4x + y = -1

-2(-2x + y = 1)
-4x + y = -1

4x -2y = -2
-4x + y = - 1

Now we add them together

4x - 4x + y - 2y = -2 - 1
y - 2y = -2 - 1
-y = -3
y = 3

Now take 3 and plug it into either equation to solve for x

-2x + y = 1
-2x + 3 = 1
-2x = -2
x = 1

So we have (1, 3)

Whoops! Hehe. I see what I did earlier.

Do you understand what I just did? I basically solved for y, then plugged y in and solved for x.

Answer 19

ohh that makes sense thanks

Answer 20

Have any more? The more we do the better you'll get.

Answer 21

i have like 4 more but i think after like 1 or 2 i will probably understand

Answer 22

Lets do another one.