Question

achar as raízes das equações

Answer 1

A)X²-X-20=0
Delta = 1²-4.1.(-20)
Delta=81
Bhaskara ;
-b+-raiz de delta / 2.a
-(-1) +-raiz de 81 / 2.1
1+-9 / 2
X'=10/2=5
X"=-8/2=-4

B)X²-3X-4=0
Delta=9+16
Delta=25
Bhaskara;
-(-3)+-5 / 2
x'=3+5/2=8/2=4
x"=3-5/2=-2/2=-1
C)X²-8X+7=0
Delta=64-28
Delta=36
-(-8)+-6 / 2
x'=8+6 /2=14/2=7
x"=8-6/2=2/2=1