Today, you will complete the square.
Find tiles to make x2 + 6x
X
X
2
X
X
X
X
X
Now arrange them to make part of a square:
X
X
X
X2
X
X
X
Use your ones blocks to complete the square:
X
X
X
X
X
X
X2
2
Complete the square for x + 10x
X
X
X
X
X
X
X
X
X
X
X2
Complete the square to form a perfect square trinomial:
x 2 + 8x +
2
x - 5x +
9.8
Solve Quadratic Equations by Completing the Square
Solve
x 2 + 16x + 15 = 0
Step 1: Write the equation in the form x 2 + bx = c
x2 + 16x = -15
Step 2: Complete the square by adding
( (
b
2
2
to both sides of the equation.
x2 + 16x +
= -15
Step 3: Factor the perfect square trinomial
Step 4: Take the square root of both sides of the equation
Step 5: Write two equations, using both the positive &
negative square root, and solve each equation.
Solve
x2 + 6x - 7 = 0
Solve
2x 2 + 16x - 18 = 0
Solve
x 2 - 6x + 10 = 0
Solve by completing the square:
x 2 - 10x = -16