Question

1.Fie a,b,c,d apartin R, astfel incat a+b=20 si c+d=30.Calculati ac+ad+bc+bd.
2.Fie x,y apartin R, x diferit de 0, astfel incat 2 supra x=y supra 3. Calculati (xy-7)la puterea 100.

Answer 1

1.a+b=20
c+d=30
ac+ad+bc+bd= a(c+d)+b(c+d)=(c+d)(a+b)=30x20=60
2)2/x=y/3
 x ori y=2ori 3
xy=6
(xy-7)^100=(6-7)^100= -1^100=  -1