Question

tìm X,   2^(x-1)+5.2^(x-2)= 7/32

Answer 1

\(\Leftrightarrow2.2^{x-2}+5.2^{x-2}=7.2^{-5}\Leftrightarrow7.2^{x-2}=7.2^{-5}\)

\(\Leftrightarrow x^{x-2}=2^{-5}\Leftrightarrow x-2=-5\Leftrightarrow x=-3\)

Answer 2

<=> \(2.2^{x-2}+5.2^{x-2}=\frac{7}{32}\) <=> \(\left(2+5\right).2^{x-2}=\frac{7}{32}\)

<=> \(7.2^{x-2}=\frac{7}{32}\)<=> \(2^{x-2}=\frac{1}{32}=2^{-5}\) => x - 2 = -5 => x = -3

Answer 3

2^x-1+5.2^x-2=7/32

=>2.2^x-2+5.2^x-2=7/32

=7.2^x-2=7/32

=>2^x-2=1/32

=>2^x-2=2^-5

=>x-2=-5

=>x=-3

vậy x=-3

Answer 4

để mk tra hộ nha