Question

Va rog sa ma ajutati
Se da numarul a=2 la puterea 1990-2 la puterea 1999-2 la puterea 1998
Aflaţi proportia a/x =4 la puterea 993/0.25

Answer 1

[tex]\displaystyle a=2^{2000}-2^{1999}-2^{1998}\\ a=2^{1998}(2^2-2^1-1)=2^{1998}\\ \frac{2^{1998}}{x} =\frac{(2^2)^{993}}{0,25}\\ x=\frac{2^{1998}\cdot2^{-2}}{2^{1986}}\\ x= \frac{2^{1996}}{2^{1986}} \\ x=2^{1996-1986}\\ x=2^{10} [/tex]

Observatie:$0,25= \frac{25}{100} = \frac{1}{4} =4^{-1}=2^{-2}$