\(\frac{2}{x-1}=\frac{3}{y-2}=\frac{4}{z.3}\)

=> \(\frac{x-1}{2}=\frac{y-2}{3}=\frac{3.z}{4}\)

=> \(\frac{2\left(x-1\right)}{2.2}=\frac{3\left(y-2\right)}{3.3}=\frac{3z:3}{4:3}\)

=> \(\frac{2x-2}{4}=\frac{3y-6}{9}=\frac{z}{\frac{4}{3}}=\frac{2x-2+3y-6-z}{4+9-\frac{4}{3}}=\frac{\left(2x+3y-z\right)-8}{\frac{35}{3}}=\frac{95-8}{\frac{35}{3}}=\frac{261}{35}\)

=> \(\hept{\begin{cases}\frac{2x-2}{4}=\frac{261}{35}\\\frac{3y-6}{9}=\frac{261}{35}\\\frac{z}{\frac{4}{3}}=\frac{261}{35}\end{cases}\Leftrightarrow\hept{\begin{cases}x=\frac{557}{35}\\y=\frac{853}{35}\\z=\frac{348}{35}\end{cases}}}\)

Câu hỏi của Nguyễn Ngọc Thảo Linh - Toán lớp 7 - Học toán với OnlineMath

Em tham khảo nhé! 

Ender Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy VclEnder Dragon Boy Vclv

có - 11/3^7.7^3 =-77/3^7.7^4 rồi so sánh với -78/3^7.7^4 nhé :))

a) \(\left[\frac{1}{3}\right]^{50}.\left(-9\right)^{25}-\frac{2}{3}:4\)

\(\Rightarrow\frac{1}{3^{50}}.\left(-9\right)^{25}-\frac{2}{3}.\frac{1}{4}\)

\(\Rightarrow\frac{\left(-9\right)}{9^{25}}-\frac{1}{6}\)

\(\Rightarrow1-\frac{1}{6}\)

\(\Rightarrow\frac{6}{6}-\frac{1}{6}=\frac{5}{6}\)

Vậy = 5/6

mình cần gấp ạ 

k mik điểm đi

\(\left|\frac{15}{32}-x\right|\ge0;\left|\frac{4}{25}-y\right|\ge0;\left|z-\frac{14}{31}\right|\ge0\) với mọi x, y, z

=> \(\left|\frac{15}{32}-x\right|+\left|\frac{4}{25}-y\right|+\left|z-\frac{14}{31}\right|\ge0\)

Vì thế nên em kiểm tra lại đê bài nhé dấu \(\le\)hay dấu \(< \)

< cô Chi. Em xem lại trong sách rồi ạ

3x - 1.x +15.1 =5/4

3x-x+15 = 5/4 

2x=5/4-15

2x=-55/4

x=-55/4:2

x= -55/8 

Xin hỏi đề bài mình viết đung chưa vì kia là chữ I hay số 1 thì mik ko rõ

e) 

\(\left(-\frac{3}{4}\right)^{3x-1}=\frac{256}{81}\)

\(\left(-\frac{3}{4}\right)^{3x}=\left(-\frac{4}{3}\right)^4\)

\(\left(-\frac{3}{4}\right)^{3x}=\left(-\frac{3}{4}\right)^{-4}\)

\(3x=-4\)

\(x=-\frac{4}{3}\)

f) \(172x^2-7^9:98^3=2^{-3}\)

\(172x^2-\frac{7^9}{\left(7^2.2\right)^3}=\frac{1}{2^3}\)

\(172x^2-\frac{7^3}{2^3}=\frac{1}{2^3}\)

\(172x^2=\frac{7^3}{2^3}+\frac{1}{2^3}=\frac{344}{8}\)

\(x^2=\frac{344}{8}:172=\frac{1}{4}\)

x=1/2 hoặc x=-1/2

Ta co: \(\frac{a}{b}=\frac{c}{d}\Leftrightarrow\frac{a}{c}=\frac{b}{d}=\frac{a-b}{c-d}\)

=> \(\frac{a}{c}.\frac{b}{d}=\frac{a-b}{c-d}.\frac{b}{d}=\frac{a-b}{c-d}.\frac{a-b}{c-d}\)

=>. \(\frac{ab}{cd}=\left(\frac{a-b}{c-d}\right)^2\)

Ta co: \(\frac{a}{b}=\frac{c}{d}=\frac{a+c}{b+d}\)

          \(\Rightarrow\frac{\left(a+c\right)^3}{\left(b+d\right)^3}=\frac{a^3}{b^3}=\frac{c^3}{d^3}=\frac{a^3-c^3}{b^3-d^3}\)