Quadratic Equations



 

Equations of the form ax2+bx+c = 0

May have two, one, or no roots (solutions)

May be solved by:

 

 

Solution by factoring

 

Solve for x:

3x2+5x=0

 

 

2x2-7x+6=0

 

 

15x2-6=x

 

 

Solution by formula

If ax2+bx+c = 0

Then x = (-b ± Ö (b2-4ac))/(2a)

 

Example

Given: x2-5x+6=0

Then: a=1, b=-5, c=6

Therefore: x=(-(-5) ± Ö(-52-4´1´6))/(2´1)

Thus: x=(5 ± Ö(25-24))/2

And: x=(5 ± 1)/2 Þ x=3 and x=2

 

Solve for x:

3x2+6x-11=0

 

 

2x2-3x=5

 

 

7x2+16=0