13. linear functions alwasys have x^1 as highest exonent for placeholder
we see that in D, we have 6x^2 which is quadratic, not linear
D is ansre
15. isolate y
emember you can do anything to an equaiton as long as you do it to both sides
12x-4y=20
add 4y to both sides
12x+4y-4y=20+4y
12x+0=4y+20
12x=4y+20
minus 20 both sides
12x-20=4y+20-20
12x-20=4y+0
12x-20=4y
divide both sides by 4
12/4x-20/4=4/4y
3x-5=1y
3x-5=y
y=3x-5
why is it not listed, there is an error in the question, report the erre
