Question

What is the value of the y variable in the solution to the following system of equation `3x − 6y = 3` and `7x − 5y = −11`?

Answer 1

Multiply each equation by an appropriate amount so that that `x` coefficients are equal, then subtract, and simplify.

(a) `3x-6y=3`
(b) `7x-5y = -11`

(c) = (a)x7
`21x -42y = 21`

(d) = (b)x3
`21x-15y = -33`

(e) = (c) - (d)
`-27y = 54`

(f) = (e)/(-27)
`y= -2`