Question

select the correct answer.
which ordered pair represents a point where the graph of $f(x)=(x - 1)(x^{2}+x - 20)$ crosses the x-axis?
(-4,0)
(20,0)
(-1,0)
(-5,0)

Explanation:

Step1: Set $f(x)=0$

To find x-axis intercepts, solve $(x-1)(x^2+x-20)=0$

Step2: Factor quadratic term

Factor $x^2+x-20$ into $(x+5)(x-4)$, so equation becomes $(x-1)(x+5)(x-4)=0$

Step3: Solve for $x$

Set each factor to 0:
$x-1=0 \implies x=1$
$x+5=0 \implies x=-5$
$x-4=0 \implies x=4$
Corresponding ordered pairs are $(1,0), (-5,0), (4,0)$

Answer:

D. (-5,0)