
Home > CAAC > Chapter 10 > Lesson 10.4.2 > Problem 10-139
10-139.
Use the quadratic formula.
Add 4 to both sides.
Solve for x.
x = −5
Complete the square.
Subtract 21 from both sides.
x2 − 10x = −25
Draw a generic rectangle.
You need 25 to complete the square.
Complete the rectangle.
Factor.
(x − 5)2 = −25 + 25
(x − 5)2 = 0
Solve for x.
x − 5 = 0
x = 5