Question

How do you solve the following system: `3x + 8y = -2, x +4y = 16`?

Answer 1

x = -34
`y = 25/2`

Explanation:

x + 4y = 16 --> x = 16 - 4y
Substitute x by (16 - 4y) into the second equation -->
3x + 8y = -2
3(16 - 4y) + 8y = - 2
48 - 12y + 8y = -2
-4y = - 2 - 48 = -50
`y = -50/-4 = 25/2` --> `x = 16 - 4(25/2) = - 34`
Check
`3x + 8y = 3(-34) + 8(25/2) = - 102 + 100 = -2`. OK