Question

[nguyen hoang phuong anh]

a) \(\dfrac{5^5}{5^x}=5^{18}\)

b) \(\dfrac{2^{4-x}}{16^5}=32^6\)

c) \(\dfrac{2^{2x-3}}{4^{10}}=8^3.16^5\)

d) \(\dfrac{2^3}{2^x}=4^5\)

e) \(9.5^x=6.5^6+3.5^6\)

f) \(7.2^x=2^9+5.2^8\)

Answer 1

[Nguyễn Lê Phước Thịnh]

a: \(\dfrac{5^5}{5^x}=5^{18}\)

=>5-x=18

hay x=-13

b: \(\dfrac{2^{4-x}}{16^5}=32^6\)

\(\Leftrightarrow2^{4-x}=\left(2^5\right)^6\cdot\left(2^4\right)^5=2^{30+20}=2^{50}\)

=>4-x=50

hay x=-46

c: \(\dfrac{2^{2x-3}}{4^{10}}=8^3\cdot16^5\)

\(\Leftrightarrow2^{2x-3}=2^9\cdot2^{20}\cdot2^{20}=2^{49}\)

=>2x-3=49

=>2x=52

hay x=26

d: \(\dfrac{2^3}{2^x}=4^5\)

\(\Leftrightarrow2^{3-x}=2^{10}\)

=>3-x=10

hay x=-7

e: \(9\cdot5^x=6\cdot5^6+3\cdot5^6\)

\(\Leftrightarrow9\cdot5^x=9\cdot5^6\)

\(\Leftrightarrow5^x=5^6\)

hay x=6

f: \(7\cdot2^x=2^9+5\cdot2^8\)

\(\Leftrightarrow2^x\cdot7=2^8\cdot7\)

\(\Leftrightarrow2^x=2^8\)

hay x=8