Question

Which of the following functions is not linear?

Answer 1

D. y = 8x² + 8x + 4

Explanation:

The equation of a linear function is in form:

`y=mx+b`

We have:

`\bold{A.}\\\\y=8(x+8)+4(x+8)\qquad\text{use the distributive property}\\\\y=8x+64+4x+32\qquad\text{combine like terms}\\\\y=12x+86\to m=12,\ b=86\\\\\bold{linear\ function}`

`\bold{B.}\\\\y=(\sqrt8)/(8)x-4\to m=(\sqrt8)/(8),\ b=-4\\\\\bold{linear\ function}`

`\bold{C.}\\\\y=(1)/(8)x+8\to m=(1)/(8),\ b=8\\\\\bold{linear\ function}`

`\bold{D.}\\\\y=8x^2+8x+4\\\\\bold{not\ linear\ function}\\\\\text{because is}\ x^2\\\\\text{It's a quadratic function}`