Question

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

Answer 1

A.) x=17 or x=1

Explanation:

Answer 2

{1, 17}

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