Question

Which statement describes the graph of f(x) = 4x2 + 20x + 25?


The graph does not intersect the x-axis.

The graph touches the x-axis at (–2.5, 0).

The graph intersects the x-axis at (–0.4, 0) and (0.4, 0).

The graph intersects the x-axis at (2, 0) and (5, 0).

Answer 1

First graph the function in a graphing calculator.

Answer 2

Intercepts the x axis, pretty sure that's when y = 0.

\[4x^{2}+20x+25 = 0 \]

\[-b \pm \frac{ \sqrt{b^{2}-4ac} }{ 2a }\]

a = 4, b = 20 c = 25

You could apply the quadratic formula to find where where f(x) = 0.

this will give you values where y = 0.

\[\sqrt{20^{2}-4(4)(25)} = 0 \]

\[\frac{ -20+0 }{ 8 } = \frac{ -5 }{ 2 } = (x_{1})\]

Answer 3

the second one???

Answer 4

(-2.5,0) the idea is that you apply the quadratic formula