4

Set 15: Quadratic Equations

Explanation

Answer: A

Convert y=2(x1)2+3y = 2(x - 1)^2 + 3 to standard form.

A.

y=2x24x+5y = 2x^2 - 4x + 5

✓ Correct
B.

y=2x22x+5y = 2x^2 - 2x + 5

C.

y=2x24x+4y = 2x^2 - 4x + 4

D.

y=2x2+5y = 2x^2 + 5

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Follow the order of operations (PEMDAS): Exponents first, then Multiplication, then Addition. 1. Expand: (x1)2=x22x+1(x - 1)^2 = x^2 - 2 x + 1. 2. Distribute: 2(x22x+1)=2x24x+22(x^2 - 2 x + 1) = 2 x^2 - 4 x + 2. 3. Add: (2x24x+2)+3=2x24x+5(2 x^2 - 4 x + 2) + 3 = 2 x^2 - 4 x + 5. Choice B is incorrect because it forgets to distribute the 2 to the middle term (2x-2 x). Choice C is incorrect because 2+3=52 +3=5, not 4. Choice D is incorrect because it ignores the middle term entirely.

Key Steps:

The correct answer is y=2x24x+5y = 2x^2 - 4x + 5

Why others are wrong:
B: Choice B is incorrect and may result from a calculation error.
C: Choice C is incorrect and may result from a calculation error.
D: Choice D is incorrect and may result from a calculation error.

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