Question

4x+7y=- 20 2x-5 y=-10

Answer 1

Answer:

x = -5 , y = 0

Step-by-step explanation:

Solve the following system:

{4 x + 7 y = -20 | (equation 1)

2 x - 5 y = -10 | (equation 2)

Subtract 1/2 × (equation 1) from equation 2:

{4 x + 7 y = -20 | (equation 1)

0 x - (17 y)/2 = 0 | (equation 2)

Multiply equation 2 by 2/17:

{4 x + 7 y = -20 | (equation 1)

0 x - y = 0 | (equation 2)

Multiply equation 2 by -1:

{4 x + 7 y = -20 | (equation 1)

0 x+y = 0 | (equation 2)

Subtract 7 × (equation 2) from equation 1:

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

0 x+y = 0 | (equation 2)

Divide equation 1 by 4:

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

0 x+y = 0 | (equation 2)

Collect results:

Answer: {x = -5 , y = 0