Question

Solve.
-5x^2+9+7x = 0−5x
2
+9+7x=0

Answer 1

x =
`\frac{-7 \frac{+}{} √(229) }{-10}`, or x=2.21327 and -0.81327

Explanation:

`-5x^2+7x+9 = 0`

see if equation is factor-able:

`\left[\begin{array}{ccc}?&9\\-5x^2&?\\\end{array}\right]`

the two ? must multiply together to
`-45x^2` and add up to 7x

no two integers times x can solve, so we must use quadratic equation

`x = \frac{-b \frac{+}{} √(b^2-4ac) }{2a}`, given a quadratic
`ax^2 +bx +c`

so

`x = \frac{-7 \frac{+}{} √(49+180) }{-10} = \frac{-7 \frac{+}{} √(229) }{-10}`