Which equation is y = 2x2 – 8x + 9 rewritten in vertex form?

a. y = 2(x – 2)2 + 9
b. y = 2(x – 2)2 + 5
c. y = 2(x – 2)2 + 1
d. y = 2(x – 2)2 + 17

C

Step-by-step explanation:

The equation of a parabola in vertex form is

y = a(x - h)² + k

where (h, k) are the coordinates of the vertex and a is a multiplier

To obtain this form use the method of completing the square

Given

y = 2x² - 8x + 9

The coefficient of the x² term must be 1, so factor out 2 from 2x² - 8x

y = 2(x² - 4x) + 9

To complete the square

add/ subtract ( half the coefficient of the x- term)² to x² - 4x

y = 2(x² + (- 2)x + 4 - 4) + 9

   = 2(x - 2)² - 8 + 9

   = 2(x - 2)² + 1 → C

range is infinite on both x and y axis positive and negative

step-by-step explanation:

the answer is b: 18

step-by-step explanation:

use the pythagorean theorem to .

a^2+b^2=c^2

plug 18 for "r"

the 2 legs are 18 and 24

18^2+24^2=c^2

324+576=c^2

900=c^2

c=30

30-12=18

18 is the radius

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