Question

Solve the system of equations using elimination.

-7x + 5y = 24
–9x + 5y = 18

A)
(9, 3)


B)
(3, 9)


C)
(
4
5
, 3)


D)
(3,
4
5
)

Answer 1

{x = 3, y = 9 thus Answer A is correct

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

Answer 2

The abswer shoul be b