Answer:
{x = 3, y = 9 thus Answer A is correct
Step-by-step explanation:
{5 y - 7 x = 24 | (equation 1)
{5 y - 9 x = 18 | (equation 2)
Swap equation 1 with equation 2:
{-(9 x) + 5 y = 18 | (equation 1)
{-(7 x) + 5 y = 24 | (equation 2)
Subtract 7/9 × (equation 1) from equation 2:
{-(9 x) + 5 y = 18 | (equation 1)
{0 x+(10 y)/9 = 10 | (equation 2)
Multiply equation 2 by 9/10:
{-(9 x) + 5 y = 18 | (equation 1)
{0 x+y = 9 | (equation 2)
Subtract 5 × (equation 2) from equation 1:
{-(9 x)+0 y = -27 | (equation 1)
{0 x+y = 9 | (equation 2)
Divide equation 1 by -9:
{x+0 y = 3 | (equation 1)
{0 x+y = 9 | (equation 2)
Collect results:
Answer: {x = 3, y = 9
