# What is 16x to the second power minus 25?

16x2 - 25 is a quadratic polynomial which defines the function f(x) = 16x2 - 25, whose graph is a parabola.

Since the x-term is missing, then the y-axis is also the axis of symmetry.

When x = 0, then f(x) = -25, so that (0, -25) is the y-intercept point, which also is the vertex of the parabola (the vertex lies on the symmetry line).

When f(x) = 0, we have

16x2 - 25 = 0 factor the difference of the two squares

(4x - 5)(4x + 5) = 0 let each factor equal to zero

4x - 5 = 0 or 4x + 5 = 0

x = 5/4 or x = -5/4

Thus, (-5/4, 0) and (5/4, 0) are the x-intercepts points.

Plot the points on a coordinate system and draw the parabola that passes through them.