Question

Solve the system. -3x + 4y = -22 2x + 7y = 5 A) (6, -1) B) (-1, 6) C) (-6, 1) D) (-1, -6)

Answer 1

A. (6,-1)

Explanation:

-3x + 4y = -22

2x + 7y = 5

x = (5 - 7y)/2

-3[(5 - 7y)/2] + 4y = -22

-15/2 + 21y/2 + 4y = -22

29y/2 = -29/2

y = -1

x = (5 - 7(-1))/2

x = 12/2

x = 6

Answer 2

A

Explanation:

We have the system of equations:

-3x + 4y = -22

2x + 7y = 5

Let's solve this using elimination, so multiply the first equation by 2 and the second equation by 3:

2 * (-3x + 4y = -22) ⇒ -6x + 8y = -44

3 * (2x + 7y = 5) ⇒ 6x + 21y = 15

Our equations are now:

-6x + 8y = -44

6x + 21y = 15

Add these two together to eliminate the x term:

-6x + 8y = -44

+ 6x + 21y = 15

______________

0x + 29y = -29

y = -29/29 = -1

Plug this back into one of the equations to find x:

-3x + 4y = -22

-3x + 4 * (-1) = -22

-3x - 4 = -22

-3x = -18

x = -18/(-3) = 6

The answer is (6, -1) or A.