Question

16) (1 Point) : Solve the equation

Answer 1

Answer:

(B)

4 +/- 3 sqrt(2) or 4+3sqrt(2) and 4-3sqrt(2)

Step-by-step explanation:

4(c-4)^2=72

4(c-4)(c-4)=72

foil the parenthesis (first, outside, inside, last)

4(c^2 -4c -4c +16)=72

4(c^2-8c+16)=72

divide each side by 4

c^2-8c+16=18

subtract 18 from both sides

c^2-8c-2

use quadratic formula

((-b +/- sqrt((-b^2)-4ac)))/2a

((-(-8)+/-sqrt((-8)^2-4(1)(-2)))/2(1))

(8+/-sqrt(64-(-8)))/2

(8+/-sqrt(64+8))/2

(8+/-sqrt(72))/2

(8+/-sqrt(36 * 2))/2

(8+/-6sqrt(2))/2

4+/-3sqrt(2)

or 4+3sqrt(2) and 4-3sqrt(2)