Question

How do you solve the system of equations `x+ y = - 4` and `- 8x + 3y = 21`?

Answer 1

x=-3 and y=-1

Explanation:

We have, `x +y=-4`
or,`y=-4-x`
Multiplying both sides with 3,we have,
`3y=-12-3x`
Substituting the value of `3y` in the equation `3y-8x=21`,we get,
`-12-3x=21+8x`
Or,`-33=11x`
Thus,`x=-3`
Putting the value of `x` in first equation,we get `y` as `-4-(-3)` or `y=-1`