#1**0 **

Solve by elimination:

{8 x + 10 y = -30 | (equation 1)

20 y - 2 x = 30 | (equation 2)

Add 1/4 × (equation 1) to equation 2:

{8 x + 10 y = -30 | (equation 1)

0 x+(45 y)/2 = 45/2 | (equation 2)

Divide equation 1 by 2:

{4 x + 5 y = -15 | (equation 1)

0 x+(45 y)/2 = 45/2 | (equation 2)

Multiply equation 2 by 2/45:

{4 x + 5 y = -15 | (equation 1)

0 x+y = 1 | (equation 2)

Subtract 5 × (equation 2) from equation 1:

{4 x+0 y = -20 | (equation 1)

0 x+y = 1 | (equation 2)

Divide equation 1 by 4:

{x+0 y = -5 | (equation 1)

0 x+y = 1 | (equation 2)

x = -5

y = 1

Guest Jul 1, 2018