1a)tìm x,y biết: \(4+\frac{x}{7+y}=\frac{4}{7}and:x+y=22\)
b)cho \(\frac{x}{3}=\frac{y}{4}\)và \(\frac{y}{5}=\frac{z}{6}\). Tính M=\(\frac{2x+3y+4z}{3x+4y+5z}\)
c) tìm x biết \(\frac{1}{4}.\frac{2}{6}.\frac{3}{8}.\frac{4}{10}...\frac{30}{62}.\frac{31}{64}=2^x\)
d)\(\frac{4^5+4^5+4^5+4^5}{3^5+3^5+3^5}.\frac{6^5+6^5+6^5+6^5+6^5+6^5}{2^5+2^5}=2x\)
2. Tính:P=\(1+\frac{1}{2}\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+...+\frac{1}{16}\left(1+2+..+16\right)\)