Answer:
x =[tex]\frac{-7 \frac{+}{} \sqrt{229} }{-10}[/tex], or x=2.21327 and -0.81327
Step-by-step explanation:
[tex]-5x^2+7x+9 = 0[/tex]
see if equation is factor-able:
[tex]\left[\begin{array}{ccc}?&9\\-5x^2&?\\\end{array}\right][/tex]
the two ? must multiply together to [tex]-45x^2[/tex] and add up to 7x
no two integers times x can solve, so we must use quadratic equation
[tex]x = \frac{-b \frac{+}{} \sqrt{b^2-4ac} }{2a}[/tex], given a quadratic [tex]ax^2 +bx +c[/tex]
so
[tex]x = \frac{-7 \frac{+}{} \sqrt{49+180} }{-10} = \frac{-7 \frac{+}{} \sqrt{229} }{-10}[/tex]
