Question

Qual o calculo de -x2 +9x -20 =0

Answer 1

-x2+9x-20 = 0. ele tá negativo

-2x+9x = 20. passa positivo

7x = 20
x = 20÷ 7
x = 2.857143

Answer 2

-x2+9x-20=0
delta = b2-4.a.c
delta=81-(-4).(-20)
delta=125
x=-b+ ou - raiz de delta
2.a
x=-9+ ou - raiz d 125
-2
x=-9+25=16=-8
-2. -2
x=-9-25=-34=17
-2. -2