Question

Find the solution to the system 4x - y = -12 and -x - y = 3

Answer 1

x = -3 , y = 0

Explanation:

Solve the following system:

{4 x - y = -12 | (equation 1)

-x - y = 3 | (equation 2)

Add 1/4 × (equation 1) to equation 2:

{4 x - y = -12 | (equation 1)

0 x - (5 y)/4 = 0 | (equation 2)

Multiply equation 2 by 4/5:

{4 x - y = -12 | (equation 1)

0 x - y = 0 | (equation 2)

Multiply equation 2 by -1:

{4 x - y = -12 | (equation 1)

0 x+y = 0 | (equation 2)

Add equation 2 to equation 1:

{4 x+0 y = -12 | (equation 1)

0 x+y = 0 | (equation 2)

Divide equation 1 by 4:

{x+0 y = -3 | (equation 1)

0 x+y = 0 | (equation 2)

Collect results:

Answer: {x = -3 , y = 0