Resposta :
-x² +2x +3
a=1,b =2,c=3
delta= b²-4.a.c
d= 2²-4.(-1).3
d=4+12
d=16
x'= -b + ou - v16/2.a
x'= -2+4/2=> x'= 2/2=>x'= 1
x"= -2-4/2=>x"=-6/2=>x"=-3
a=1,b =2,c=3
delta= b²-4.a.c
d= 2²-4.(-1).3
d=4+12
d=16
x'= -b + ou - v16/2.a
x'= -2+4/2=> x'= 2/2=>x'= 1
x"= -2-4/2=>x"=-6/2=>x"=-3