Question

-x²+12x+20=0? me ajudem por favor

Answer 1

Vamos la

Δ=$b^2-4ac$
Δ=$12^2-4*(-1)*(20)$
Δ=$144-(-80)$
Δ=$144+80$
Δ=224
√Δ=√224 = 4√14
$x1= \frac{-12+4 \sqrt{14} }{2*(-1)} \\ x1= \frac{-12+4 \sqrt{14} }{-2} \\ x1= 6+2 \sqrt{14} \\ \\ x2= \frac{-12-4 \sqrt{14} }{2*(-1)} \\ x2= \frac{-12-4 \sqrt{14} }{-2} \\ x2= 6-2 \sqrt{14}$