Answer:
x = 225/67 , y = -133/67 or decimal x≈3.3582 and y≈-1.9851, thus a. is the answer rounded.
Explanation:
Solve the following system:
{8 x + 9 y = 9 | (equation 1)
3 x - 5 y = 20 | (equation 2)
Subtract 3/8 × (equation 1) from equation 2:
{8 x + 9 y = 9 | (equation 1)
0 x - (67 y)/8 = 133/8 | (equation 2)
Multiply equation 2 by 8:
{8 x + 9 y = 9 | (equation 1)
0 x - 67 y = 133 | (equation 2)
Divide equation 2 by -67:
{8 x + 9 y = 9 | (equation 1)
0 x+y = -133/67 | (equation 2)
Subtract 9 × (equation 2) from equation 1:
{8 x+0 y = 1800/67 | (equation 1)
0 x+y = -133/67 | (equation 2)
Divide equation 1 by 8:
{x+0 y = 225/67 | (equation 1)
0 x+y = -133/67 | (equation 2)
Collect results:
Answer: {x = 225/67 , y = -133/67