Question

1. Solve the system by the elimination method.

3x−5y=4
−9x+3y=−24
A. (2, −2)
B. (3, 1)
C. (1, −1)
D. (8, 4)
2. Manny says he should multiply the first equation in the system of equations below by 3 and the second equation by 2, then add to eliminate x. Is there a more efficient way to solve this system? Explain your answer.
−2x+y=15
3x+4y=−12
A. No, there isn't a more efficient way to solve this system.
B. Yes, a more efficient way is to multiply the first equation by −4
add to eliminate y, then solve for x.
C. Yes, a more efficient way is to multiply the first equation by −4
add to eliminate x, then solve for y.
D. Yes, a more efficient way is to multiply the first equation by 4
add to eliminate y, then solve for x.

Answer 1

x = 3 and y = 1

Explanation:

A) most efficient way is to multiply the first equation by 3 to eliminate the 'x' terms and get 9x - 15y = 12

if you add this to -9x + 3y = -24 you will get -12y = -12

y = 1

substitute 1 for 'y' to get 'x': 3x - 5 = 4

3x = 9

x = 3