Question

What is the solution of the system?

5x+6y=20
9x+11y=32

•(28, -20)
•(28, 20)
•(-28, 20)
•(20, -28)

Answer 1

The correct option is 1.

Explanation:

The system of equations is

`5x+6y=20` ....(1)

`9x+11y=32` ....(2)

Multiply equation (1) by 11.

`55x+66y=220` ....(3)

Multiply equation (2) by 6.

`54x+66y=192` ....(4)

Subtract equation (4) from equation (3).

`55x+66y-54x-66y=220-192`

`x=28`

Substitute x=28 in equation (1).

`5(28)+6y=20`

`140+6y=20`

`6y=-120`

`y=-20`

Therefore the solution of the given system of equations is (28,-20). Option 1 is correct.