how can i get x and y intercepts for (f)=4x^2_x+20?

Question

anonymous · Answer

find out what # is x

anonymous · Answer

to get the y-intercept, turn the x value and solve for y
to get the x-intercept, factor the function, the equal it to 0 and solve for the x

whpalmer4 · Answer

$$f(x) = 4x^2-x+20$$
x-intercept is where $y = f(x) = 0$
y-intercept is where $y = f(0)$

Clearly, the y-intercept is easy enough to find: $y = f(0) = 4(0)^2-(0)+20 = $

The x-intercept is a bit trickier.  You can factor the equation and set each factor equal to 0, then solve for the value of $x$; you can use the quadratic formula $$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$$where the polynomial is in form $ax^2+bx+c=0$ so here $a=4, b=-1,c=20$; and there are other methods that probably aren't what your teacher wants you to do.  Do you know how to factor $4x^2-x+20$?