Which of the quadratics has a graph with only one x-intercept?

A)
y = 2x^2 + 4

B)
y = x^2 - 8x + 16

C)
y = 2x^2 - 8x + 20

D)
y = -2(x -1)^2 + 2

Question

Which of the quadratics has a graph with only one x-intercept?

A)
y = 2x^2 + 4

B)
y = x^2 - 8x + 16

C)
y = 2x^2 - 8x + 20

D)
y = -2(x -1)^2 + 2

australopithecus · Answer

to find an x-intercept
set

y = 0

You might want to factor

directrix · Answer

One way to think about the problem is to look at the options and ask yourself which one of them is a perfect square trinomial. That's where you will get a double root which appears as one root on the graph. 

The pattern for a perfect square trinomial is attached.

Think Shakespeare paraphrases here for your answer: "2b or not 2b, that is the answer to the question.