Question

The roots of the equation 9x^2+3x-4=0 are

1) imaginary
2) real rational and equal
3) real rational and unequal
4) real irrational and unequal

Answer 1

What do we get from the Quadratic formula?
\[\frac {-3\pm \sqrt{9+144}}{18}=\]

Answer 2

check
\[b^2-4ac=9^2-4\times 9\times (-4)=225=15^2\] since the discriminant is a perfect square, you have two rational roots