Question

$f(x) =x2 - 9x = 20$
​

Answer 1

Resposta:

$x^2-9x=20\\x^2-9x-20=0$

Δ=$b^2-4ac\\81-4(1)(-20)\\161$

$x= \frac{-b+\sqrt{161}}{2a\\\\\\}\\x1=\frac{9+\sqrt{161} }{2}$

$x2=\frac{9-\sqrt{161} }{2}$