Question

Which is the graph of f(x) = (x - 1)(x + 4)?

Answer 1

last graph

Explanation:

Answer 2

You can determine this by finding zeros of quadratic function,

`(x-1)(x+4)=0\implies x_1=1, x_2=-4`.

Which eliminates first and third option.

Now we have up and down parabolas left.

If we factor
`(x-1)(x+4)=x^2+4x+\dots` we find that the coefficient before
`x^2` determines how it is turned, since its positive its an upward turned parabola hence the answer is the last graph.

Hope this helps.