Question

Is f(x)=x(x+5) a linear function?

Answer 1

Let us expand that

$\sf f(x)=x(x+5)$
$\sf f(x)=x^2+5x$

Since it has $\sf x^2$ in it, it is now a linear function.

So the answer is $\sf \boxed{No, ~this~ is~ not~ a ~linear ~function.}$

Answer 2

F(x)= x(x+5)
= x²+5x
this is not a linear function as it is not in the form y=mx+b
it is a quadratic function with x intercepts at 0 and -5 and y intercept 5