Question

(A-2)(a-7) alguém poderia me ajudar??

Answer 1

(A-2)(a-7)=
a^2-7.a-2.a+14
a^2-9a+14=0

∆= b^2-4.a.c
∆=(-9)^2-4.1.14
∆=81-56
∆=25

x=-b+-√∆/2.a
x=9+-5/2.1

x1=9+5/2=14/2=7

x2=9-5/2=4/2=2

S={7,2}