1. Which of the following is the standard form of y = (x – 3)(x – 7)? a. y = (x + 5)2 – 21
b. y = (x - 5)² - 4
c. y = (x + 5)2 - 4
d. y = (x – 5)2 + 28
A
B

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  b.  y = (x - 5)² - 4

Step-by-step explanation:

Here, we take "standard form" to mean "vertex form."

In the US, "standard form" would be ...

  y = x² -10x +21

Vertex form is ...

  y = (x -5)² -4 . . . . matches B

d

step-by-step explanation:

d