Question

How do you solve `x(2x + 3) = 9`?

Answer 1

-3 and `3/2`

Explanation:

Bring the equation to standard form:
`y = 2x^2 + 3x - 9 = 0`
Use the improved quadratic formula to solve this equation.
`D = d^2 = b^2 - 4ac = 9 + 72 = 81` ---> `d = +- 9`
There are 2 real roots:
`x = -b/(2a) +- d/(2a) = -3/4 +- 9/4 = (-3 +- 9)/4`
`x = -12/4 = - 3`
`x = 6/4 = 3/2`