Question

determine as raizes reais destas equações de 2° grau
a) 4(x+1)-(x-4)(x+4)=4x
b) (a-1)^2 - a+5=-3(a+1)
c) (x-4) (x-5)=20
d) (2y-1)^2 =1

Answer 1

a)4(x+1)-(x-4)×(x+4)=4x
4x+4-(4^2-16)=4x
4-x^2+16=0
20-x^2=0
-x^2=-20
x^2=20
x=+ou- 2 raiz de 5
x=2 raiz de 5
x=-2 raiz de 5
x`=-2 raiz de 5, x``=2 raiz de 5


d)2y-1=+ou- 1
2y-1=1
2y-1=-1
y=1
y=0
y`=0,y``=1