Question

How to find X-7y=-21 13x-7y=63

Answer 1

Answer:

y = 4

x= 7

Step-by-step explanation:

First you would rearrange the first equation x-7y=-21 and make x the subject:

x= -21 +7y

Then substitute x into the 2nd equation to find y:

13x - 7y= 63

13(-21+7y) - 7y = 63

-273 + 91y -7y = 63

-273 + 84y=63

84y = 63 + 273

84y = 336

y = 4

Once you have y you can substitute this into any of the original equations to find x, for example:

x - 7y = -21

x - 7(4) = -21

x - 28 = -21

x = -21 +28

x= 7