19)

Solve the quadratic equation x2 - 18x + 81 = 64 for x.

A)

x = 17 or x = 1

B)

x = 11 or x = - 5

C)

x = 9 or x = - 8

D)

x = 2 or x = 9

A.) x=17 or x=1

{1, 17}

Step-by-step explanation:

x2 - 18x + 81 = 64 can be rewritten as x² - 18x + 81 = 64.

Next, x² - 18x + 81 can be rewritten as (x - 9) ²

so that we now have:

(x - 9) ² = 64.

Taking the sqrt of both sides, we get

x - 9 = ± 8

Then one root is x = 9 + 8 = 17, and the other is x = 9 - 8 = 1.

{1, 17} is the set of roots