Question

solve this equation by using systems of elimination please!
-x+5y=13
x-y=15

Answer 1

elimination is the process of stacking them together and adding them (or subtracting them) so that variable(s) are eliminated.

try adding them together.

Answer 2

Eliminating the x's you're left with \[4y = 28\]\[y = 7\] Plugging 7 in one of the equations you get \[x - 7 = 15\]\[x = 22\] So the solution is \[(22,7)\]

Answer 3

thank you!!

Answer 4

could you help me with this one too?

4x-7y=3
x-7y= -15

Answer 5

Multiply one of the equations by -1 so you can eliminate the 7y's

Answer 6

It doesnt matter which one

Answer 7

so then:
(4x-7y=3) -1=
-4x+7y= -3
x-7y= -15
and that would be...
3x= -18?

Answer 8

-3x = -18.. you where close

Answer 9

Then when you plug x back into one of the equations be sure to use the equations that where given

Answer 10

Not the equation you multiplied -1 by

Answer 11

really? yesss. so even if the x's are negative i still add them? never actually subtract? because what i did was:
4x-x= 3x
and what i was supposed to do was:
-4x+x= =3

Answer 12

I should say. not the equation you got when you multiplied it by -1

Answer 13

well if you subtract them you would get -4x - x = -5x

Answer 14

ya i know, thats what i keep forgetting about. like i actually subtracted them instead of adding them. is there a time when i actually COULD subtract them? so then to solve for y it would be:
6-7y= -15
-6 -6
-7y/-7y= -21/-7y
y= 3?

Answer 15

so you would get x to be 6.. then plug x back into one of the original equations and you get \[6 - 7y = -15\]\[-7y = -21\]\[y = 3\] So the solution is (6,3).. and to check this plug in both numbers into one of the equations \[6 - 7(3) = -15\]\[6 - 21 = -15 \space {\checkmark}\] So its correct :)

Answer 16

YAY!! thank you sooo much :D i really appreciate it :)

Answer 17

No problemm