Question

Find the x intercepts of y=2x^2+x-21

Answer 1

The x intercept is when y=0. Substitute: 

$2x^2+x-21=0$

Solve for x by factoring.

$2x^2-6x+7x-21=0$

$=2x(x-3)+7(x-3)=0$

$=(x-3)(2x+7)=0$ 

$x=3$ AND $x=-\frac{7}{2}$ 

So therefore, we have our intercepts: 

(3,0) & (-7/2,0) 

Hope that helped!

~Cam943, Moderator