Question

Solve the system of equations
-2x - 2y = -4
2x - y = -5

Answer 1

A. (-1,3)
B. (3,-1)
C. (-1,-3)
D. (-3,-1)

Answer 2

add them...
-2x - 2y = -4
2x - y = -5
------------

First, what does -2x + 2x equaal ?

Answer 3

*equal -- typo

Answer 4

0?

Answer 5

correct.
Now what does -2y + (-y) equal ?

Answer 6

I'm sorry, I have no clue.

Answer 7

when the signs are the same, negative or positive, you add them. -2y + (-y) =- 3y. Now if the signs would have been different, and the problem would have been 2y + (-y), then you would subtract and take the sign of the largest number and this one would equal 1y or just y.
Anyways, the signs were the same, both negative, so you just add them. Do you understand ?

Answer 8

Yes, thank you.

Answer 9

now , lets finish...
-4 + (-5).....what does that equal ?

Answer 10

-9?

Answer 11

correct.
-2x - 2y = - 4
2x - y = - 5
-------------(add)
0 _ 3y = - 9
-3y = - 9
Do you know how to solve for y ?

Answer 12

Um..*sigh* Sort of. I suck at math.

Answer 13

-3y = - 9
we need to get y by itself. To do this, we do the opposite of what the problem is doing. Let me try to show you...um.....-3y means -3*y. It is multiplying. We do the opposite, and divide. If we divide by -3 (on both sides), it will get y by itself.
-3y/-3 = -9/-3.
the -3's divide to make 1y = -9/-3 (keep in mine, when you are dividing by two numbers with the same sign, it changes the sign to a positive. So, -9/-3 = 3. Can you kinda understand that ? I am not real good at explaining.
Anyways....y = 3

Answer 14

So, it can't be C or D..Right?

Answer 15

right.
we know that y = 3. To find x, we sub 3 in for y in either of the original equations.
2x - y = - 5
2x - 3 = - 5 (now you add 3 to both sides to get 2x by itself)
2x - 3 + 3 = - 5 + 3 (combine like terms)
2x = - 2 (divide by 2 to get x by itself)
2x/2 = - 2/2
x = - 1
Can you see what I did ? Does it make sense ?

Answer 16

Okay. I get it. Simple equations! Thank you so much! Would it be B then?

Answer 17

lets see.....x = -1 and y = 3. In the ordered pair (x,y).....x comes first.So the answer is (-1,3)....which is A. Remember, x comes first.
You will need to study more on your signs, but other then that, you got this. Good job.

Answer 18

Do you have any more questions ?

Answer 19

well.....um...if so, tag me and I might can help you. If not, have a nice day :)

Answer 20

Dang, I remember that now. (x,y) Thank you so much!!!!! @texaschic101