Question

Determine, sem usar a fórmula resolutiva, as raízes reais das equações.


A) x2-5x+6=0

B) x2-2x-120=0

Answer 1

A)
x2-5×+6=0
x2-(5×6)=
x2-30

B)
x2-2x-120=0
×=1 (-2+/-√(-2)2-4×1×(-120)
2×1
x=2+/-√4+480
2
x=2+/-√484
2
x=2+/-22
2
x1=2+22
2
x2=2-22
2
(x1=-10, x2=12)