A quadratic equation is an equation of theform ax² + bx + c = 0, where a
. We can solve equations of this form by identifying a, b and c andsubstituting them into the formula
tofind 
.
Example: Solve 
Then
or 
It is very important to get the correctvalues of 
,
,and 
.For the following equations the values are given
Notice that if a minus sign appears in theformula we have to solve then that value of ,orwill be negative.
Then for the first equation 
We may also solve quadratic equations bysketchinga quadratic graph or by completingthe square.
Example:Solve
Then
or