Without solving the equation , find the sum of its roots.
A quadratic equation can be written in the form ,
and dividing both sides by gives the form
Suppose the two roots of a quadratic equation are and . The
sum of the two roots, or , is equal to , and
the product of the two roots, or , is equal to .
Thus, the form of a quadratic equation can also be written as
Multiply the factors on the left
side of the equation.
Divide both sides of by 56.
Therefore, is equal to , or the sum of the
two roots of the equation.