Use completing the square to solve for x in the equation (X + 7) (x-9) = 25

x = - 4 or 6

x = - 2 or 14

x=1 + 789

X=1V87

x = 1 ±√89

Step-by-step explanation:

Expand (X + 7) (x-9) = 25:

x^2 + 7x - 9x - 63 = 25

This becomes:

x^2 - 2x - 63 = 25, or

x^2 - 2x = 88

To complete the square: Take half of the coefficient of x (which is - 2), and square the result, obtaining + 1.

Add + 1 to both sides:

x^2 - 2x + 1 = 88 + 1 = 89

Rewriting x^2 - 2x + 1 as the square of the binomial x - 1:

(x - 1) ^2 = 89

Taking the sqrt of both sides:

x - 1 = ±√89

Solve for x. Add 1 to both sides:

x = 1 ±√89