Question

How can i get an elimination out of this equatio

Answer 1

The simultaneous equations are:

`\begin{gathered} -2x+7y=-23 \\ 6x-7y=-1 \end{gathered}`

Since, the unknown y has the same co-efficient across the two(2) equations, we can eliminate it directly.

Thus, we have:

`\begin{gathered} -2x+7y=-23 \\ 6x-7y=-1 \\ ----------- \\ -2x+6x=-23-1 \\ 4x=-24 \\ x=(-24)/(4) \\ x=-6 \end{gathered}`

To find y, substitute for x = -6 into any of the equations.

Thus, we have:

`\begin{gathered} \text{from equation i)} \\ -2x+7y=-23 \\ -2(-6)+7y=-23 \\ 12+7y=-23 \\ 7y=-23-12 \\ 7y=-35 \\ y=-(35)/(7) \\ y=-5 \end{gathered}`

Hence, the correct option is option A