Question

Solve the equations using elimination method:
$x-6y=9$ and $2x-y=7$

• A. (-3, -1)
• B. (3, -1)
• C. (-3, 2)
• D. (3, 1)

Answer 1

The correct option is B (3, -1)

$x-6y=9$ ----- (1)
$2x-y=7$----- (2)
Multiply equation (1) by 2 and then subtract equation 1 and 2,
$2x-12y=18$
$2x-y=7$
(-) (+) (-)
___________
$11y=-11$
$y=\frac{-11}{11}=-1$
Put the value of y in equation (2), we get
$2x-y=7$
$2x(-1)=7$
$2x=71$
$2x=6$
$x=\frac{6}{2}=3$
Therefore the solution is $(3,-1)$.