Page 673 - Algebra 1

2x - 5 = 0 2x = 5
x = 2.5
4x2 -25= 0 4(2.5)2 -25 0 4(6.25)-25 0 25 - 25 0 0=0
2x + 5 = 0 2x = -5
x = -2.5
Set each factor equal to zero. Solve each equation for x.
Check
Solving Quadratic Equations with Missing Terms
Example
5
Solve.
a. 18x2=8x SOLUTION
18x2 - 8x = 0 2x(9x - 4) = 0 2x = 0 x= 0
Check
18x2 = 8x 18 · (0)2 8(0)
Set the equation equal to zero. Factor out the GCF.
9x - 4 = 0 Set each factor equal to zero. x = _4 Solve each equation for x.
9
18x2 = 8x
_42 _4 18(9) 8(9)
0=0✓ __ 18(16 ) 8(4 )
The solution set is ⎨⎧0, _4 ⎫⎬. ⎩9⎭
b. 4x2-25=0 SOLUTION
4x2 - 25 = 0 (2x - 5)(2x + 5) = 0
The solution set is {-2.5, 2.5}.
✓
4x2 -25= 0 4·(-2.5)2 -25 0 4(6.25) - 25 0 25 - 25 0
0=0 ✓
32=32 ✓ __
99
Set the equation equal to 0. Factor.
81 9
658 Saxon Algebra 1