Solving Quadratic Expressions by Factoring

Solve by Factoring Completely: 3x² + 18x +15 = 0 Hint: Factor GCF first.

• x=5 x=-1

• x=3 x = 1

• x= -5 x= - 1

• x= -5 x = 1

Solve by factoring: x² = 9x - 20

• x = -4 and x = -5

• x = 20 and x = -9

• x = 4 and x = 5

• x = -4 and x = 5

Solve by factoring:  2x²+ 7x + 6 = 0

• x= 3/2 and x = 2

• x = -3/2 and x = -2

• x = 6 and x = 7

• x = -6 and x = -7

• x= 0 or x = 3

• x = 0 or x = -3

• x = 3

• x = -3

Solve by factoring: 5x² + 13x + 6 = 0

• x = -2 and x = -3/5

• x = 2 and x = 3/5

• x = -2 and x = 3/5

• x = 2 and x = -3/5

Solve.

x² - x - 90 = 0

• x = 9, x = 10

• x = 9, x = -10

• No Real Number Solutions

• x = -9, x = 10

Solve by factoring: x² + 3x - 18 = 0

• x = -3 and x = 6

• x = 3 and x = -6

• x = -9 and x = 2

• x = 9 and x = -2

Solve for the values of x:
(x - 3)(x + 6) = 0

• { -3, -6 }

• { 3, -6 }

• { -3, -6 }

• { 3, 6 }

What is the first step in solving 
(x + 2)(x - 3) = 0      ?

• Plug in zero for x

• Solve for x

• FOIL

• Set each binomial factor equal to zero

Solve:

k² - 2k - 24 = 0

• k = -4, 6

• k = -4, -6

• k = -6, 1

• k = 4, -6