8
advanced-math

Find the zeros of f(x)=2x2−8xf(x) = 2x^2 - 8x.

A

0,40, 4

B

0,−40, -4

C

2,42, 4

D

−2,4-2, 4

Correct Answer: A

Choice A is the correct answer. Set f(x)=0f(x) = 0 and factor.

  1. 2x2−8x=02x^2 - 8x = 0.
  2. Factor out GCF 2x2x: 2x(x−4)=02x(x - 4) = 0.
  3. Solve: 2x=0⇒x=02x = 0 \Rightarrow x = 0 and x−4=0⇒x=4x - 4 = 0 \Rightarrow x = 4.

Choice B is incorrect because of sign error on 4. Choice C is incorrect because it misses 0. Choice D is incorrect because it misses 0.

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Set 8: Quadratic Equations and Functions 8