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Which equation is best to use to determine the zeros of the graph of y = 4x^2 – 8x - 5?

(2x + 1)(2x - 5) = 0
(2x - 1)(2x - 5) = 0
(4x - 1)(x - 5) = 0
(4x + 1)(x - 5) = 0 ​

Which equation is best to use to determine the zeros of the graph of y = 4x^2 – 8x-example-1
User Gerum
by
6.2k points

1 Answer

5 votes

Answer:

(a) (2x +1)(2x -5) = 0

Explanation:

The best equation to use to find the zeros is the one that represents the correct factored form of the given equation. The only factoring that is correct is ...

(2x +1)(2x -5) = 0

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Additional comment

This tells you the zeros are x = -1/2 and x = 5/2.

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The factoring can be checked by checking each of the terms of the product. The leading term is the product of leading terms, 4x² in every case, so that is uninformative.

The constant is the product of the constants, so only (1)(-5) gives the correct -5 constant (eliminates B and C).

The linear term is (4)(-5) +(1)(1) = -19 for the last choice, so that is incorrect. It is (2)(-5) +(1)(2) = -8 for the first choice, so that is the correct factorization.

User Julio Marins
by
6.5k points
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