Math
posted by Enrique .
Solve the equation by first factoring the quadratic expression.
1. x2+4.5x=0 2. x29x=0 3. x2+10x=0

1.
x ^ 2 + 4.5 x = 0
x ^ 2 + 9 x / 2 = 0
x / 2 ( 2 x + 9 ) = 0 Multiply both sides by 2
x ( 2 x + 9 ) = 0
First solution:
obviously x = 0
Second solution:
2 x + 9 = 0 Subtract 9 to both sides
2 x + 9  9 = 0  9
2 x =  9 Divide both sides by 2
x =  9 / 2
Solutions are x = 0 and x =  9 / 2
2.
x ^ 2  9 x = 0
x ( x  9 ) = 0
First solution:
obviously x = 0
Second solution:
x  9 = 0 Add 9 to both sides
x  9 + 9 = 0 + 9
x = 9
Solutions are x = 0 and x = 9
3.
 x ^ 2 + 10 x = 0
x (  x + 10 ) = 0
First solution:
obviously x = 0
Second solution:
 x + 10 = 0 Subtract 10 to both sides
 x + 10  10 = 0  10
 x =  10 Multiply both sides by  1
x = 10
Solutions are x = 0 and x = 10