Question

Solve the quadratic equation 3x^2 +x-5=0 give your answers to two decimal places

Answer 1

Especially if we're to present the answers to 2 decimal places, we'd gues that the roots of this polynomial are not "nice."

My suggestion is that we use the quadratic formula to find the roots, and then write the associated factors.

In 3x^2 +x-5=0, a=3, b=1 and c= -5. Thus, the roots are

-1 plus or minus √(1^2 - 4(3)(-5) )

x = --------------------------------------------------

2(3)

or:

-1 plus or minus √61 -1 plus or minus 7.81

x = ----------------------------------- = ---------------------------------

6 6

Then one root is 6.81/6, or approx. 1.14, and the other is

-8.81/6, or approx. -1.47.

The solution set is then {-1.47, 1.14}.