Question

x(x - 2) + 1 = 2 (x + 3) calcule ?

Answer 1

x(x - 2) + 1 = 2 (x + 3)
x²-2x+1=2x+6
x²-2x+1-2x-6=0
x²-4x-5=0 {Equação do 2° grau}
a= 1
b= -4
c= -5
∆=b²-4ac
∆= (-4)²-4.1.(-5)
∆= 16+20
∆=36
x= -b +- √∆ /2a
x= -(-4) +- √36 /2.1
x= 4 +- 6 /2
X'= 4+6/2= 10/2= 5
X"= 4-6/2= -2/2= -1