Ta có ; \(\frac{x-1}{2}=\frac{y+3}{4}=\frac{z-5}{6}=\frac{3x-3}{6}=\frac{3y+9}{12}=\frac{5z-25}{30}\)

\(\frac{5z-25-\left(3x-3\right)-\left(3y+9\right)}{30-12-6}=\frac{5z-25-3x+3-3y-9}{12}\)\(=\frac{5z-3x-3y-\left(25-3+9\right)}{12}=\frac{50-31}{12}=\frac{19}{12}\)

Nên \(\frac{x-1}{2}=\frac{19}{12}\Rightarrow x-1=\frac{19}{6}\Rightarrow x=\frac{25}{6}\)

       \(\frac{y+3}{4}=\frac{19}{12}\Rightarrow y+3=\frac{19}{3}\Rightarrow y=\frac{10}{3}\)

       \(\frac{z-5}{6}=\frac{19}{12}\Rightarrow z-5=\frac{19}{2}\Rightarrow z=\frac{29}{2}\)

Đặt \(\frac{a-b}{a}=k\Rightarrow a-b\)\(=ak\)

\(\frac{a-b}{a}=\frac{ak}{a}=k\)

Đặt \(\frac{c-d}{c}=k\Rightarrow c-d=ck\)

\(\frac{c-d}{c}=\frac{ck}{c}=k\)\(=k\)

Vậy\(\frac{a-b}{a}=\frac{c-d}{c}\).

1 \(=\)\(\frac{46656}{216}\)\(=\)216

2\(=\)\(\frac{64}{1024}\)\(=\)\(\frac{1}{16}\)

3 \(=\)\(\frac{900}{-27000}\)\(=\)\(\frac{-1}{30}\)

4 \(=\)\(\frac{225}{-3375}\)\(=\)\(\frac{-1}{15}\)

1+1+2+3+5+8.......+89

Ta se ket hop cho dau tien vao

1+1=2

2+2=4

4+3=7

7+5=12

12+8=20

Vay chung ta se co ket qua la 20

Lay 89 tru 20 bang 69 na

Vay : 1+1+2+3+5+8+69+89 = 178

Dung thi k cho minh con sai thi thoi nha

Minh hoc lop 3