Question

Which ordered pair is the solution to the system of equations?



A.
(2, −3)

B.
(−2, 1)

C.
(5, −2)

D.
(−6, 5)

Answer 1

http://static.k12.com/bank_packages/files/media/mathml_8dbf6dd9d4acbd8b54a2dc201e4768407b59a1c1_1.gif

Answer 2

it is A

Answer 3

plug in 2 for x and -3 for y

Answer 4

ok can you explain why it is A?

Answer 5

We can re-order the first equation:

x + y = -1

Subtract 1 to both sides:

x = -y - 1

Now we can plug in -y - 1 for 'x' in the 2nd equation.

x - 3y = 11

-y - 1 - 3y = 11

Simplify:

-4y - 1 = 11

Can you finish that?

Answer 6

@Glorm321 Don't give answers.

Read the Code of Conduct:

http://openstudy.com/code-of-conduct

Answer 7

no sorry not really good at math anymore

Answer 8

so two plus negative three is negative 1

Answer 9

2 minus negative three times negative three equals 2+9 which equals 11

Answer 10

thanks that really helps : )

Answer 11

and I am actually new so I did not know about the code of conduct! @iGreen.

Answer 12

do you understand the problem?

Answer 13

its cool at least you explained it for me and yes thank you can you help with a few more?

Answer 14

@Glorm321

Yes, I can see that.

But please, in the future, guide them to the answer so that they get it on their own. Don't give them the answer AT ALL.

Answer 15

lol and i'm new too i just started yesterday

Answer 16

well I will give you a tip @TeenWolfGirl , when you are given a problem with coordinates, plug them into the equation

Answer 17

ok

Answer 18

i don't mean to be a bother but can you, one more time, explain it plz

Answer 19

@iGreen can you plz explain it again?

Answer 20

Okay, so we first rearrange the first equation so that we can substitute.

x + y = -1

For us to substitute we have to get one of the variables on one side by itself.

So we can subtract 'y' to both sides.

x = -y - 1

So now we can plug in -y - 1 into the 2nd equation:

x - 3y = 11

-y - 1 - 3y = 11

Answer 21

Then we simplify it and solve for 'y'.

Answer 22

Do you understand?

Answer 23

kinda sorry i am taking so like i am writing this down so that i an study it

Answer 24

Okay, no problem.

Answer 25

Our next step would be to simplify '-y - 3y', which is the same thing as '-1 - 3', then we add a 'y' after it. So that gives us -4y.

Plug that back in:

-4y - 1 = 11

Now we add 1 to both sides to get the variable by itself.

-4y = 12

Then, our last step is to divide -4 to both sides, which gives us:

y = -3

Answer 26

Now we have the y-value of the solution. We have to plug in y = -3 into any of the two original equations to find the x-value.

x + y = -1

Plug in -3 for y:

x - 3 = -1

Add 3 to both sides:

x = 2

So x = 2, so our final answer is x = 2, y = -3, or (2, -3).