Question of college algebra

[inertia2018]

Can someone explain how the values of x and y are 30 and -9? This question is from instantcert, college algebra test.


Solve for x and y:


Solve for x and y:

Correct answer: 30, -9.

I had the answer as 6, -3.

[ROYISAGIRL]

-2(30) - 4(-9)=-24
-60--36=-24
-60+36=-24
2(30) + 8(-9)=-12
60 + -72=-12

[bluebooger]

I think you forgot about your signs

the positive 2x and negative 2x add to zero

negative 4y adds to positive 8y
giving you positive 4y

negative 24 and negative 12 give you negative 36

negative 36 divided by positive 4y gives you
negative 9

[dfrecore]

If you divide everything in the 1st set by -2, and then you divide everything in the 2nd set by 2, you can then set up both sets as x=...

Then, just solve for y.