Question

Which of the quadratics has a graph with only one x-intercept?
A)
y = 2x2 + 4
B)
y = x2 - 8x + 16
C)
y = 2x2 - 8x + 20
D)
y = -2(x -1)2 + 2

Answer 1

y = x2 - 8x + 16

Answer 2

Agree. If you solve it using the Quadratic Formula, you will find that it can be rewritten as \[(x-4)^2\], which has only one root at x = 4.