Question

Quanto é (a-7) (a-9)=

Answer 1

(a-7).(a-9)

=a²-9a-7a+63

=a²-16a+63

Answer 2

(a-7).(a-9)
a^2-9a-7a+63
a^2-16a+63=0
delta=b^2-4ac
delta=(-16)^2-4.1.63
delta=256-252
delta=4
a=-b-/+ raiz de delta/2a
a=-(-16)-2/2.1
a=16-2/2
a=14/2
a=7
a=-(-16)+2/2.1
a=16+2/2
a=18/2
a=9
S={(7, 9)}