Question

cứu

Answer 1

\(7)\dfrac{3}{5}\cdot4^x=\dfrac{3}{5}\cdot4^5\\ 4^x=4^5\\ x=5\\ 8)\dfrac{3}{2}\cdot5^x=\dfrac{3}{2}\cdot5^{12}\\ 5^x=5^{12}\\ x=12\\9)6\cdot8^{x-1}+8^{x+1}=6\cdot8^{19}+8^{21}\\ 8^{x-1}\left(6+8^2\right)=8^{19}\cdot\left(6+8^2\right)\\ 8^{x-1}=8^{19}\\ x-1=19\\ x=19+1\\ x=20\\ 10)5\cdot2^x+3\cdot2^{x+2}=5\cdot2^5+3\cdot2^7\\ 2^x\cdot\left(5+3\cdot2^2\right)=2^5\cdot\left(5+3\cdot2^2\right)\\ 2^x=2^5\\ x=5\)