Question

Consider the following system of equations:

Equation 1: 8x+2y=308x+2y=30
Equation 2: 7x+2y=247x+2y=24


What can we do to eliminate that variable pair?

(There are 2 correct answers. Please select both.)



Add the two equations.


Subtract Equation 2 from Equation 1.


Divide the two equations.


Multiply one equation by -1, then add the two equations.

Answer 1

x = 6 ; y = -9

Explanation:

8 x + 2 y = 30 ..........equ No 1

7 x + 2 y = 24......... equ No 2

8 x = 30 - 2y

∴ x =
`( 30 - 2 y)/(8)`

substituting the value of x in equ No 2

7
`(30 - 2 y)/(8)` + 2 y = 24

7 ( 30 -2 y) + 2 y × 8 = 24 × 8

7 × 30 - 14 y + 16 y = 192

210 + 2 y = 192

2 y = 192 - 210

2 y = - 18

∴ y = - 9

put y = -9 , 8 x = 30 - 2 y

8 x = 30 - 2 ( -9)

8 x = 30 - ( -18)

8 x = 48

∴ x = 6

x = 6 ; y = -9