cuộc học hôm nay vui nghỉ

chịu em lớp 5 mè

1)

\(\frac{x-1}{2}=\frac{y+3}{4}=\frac{z-5}{6}=\frac{3x-3}{6}=\frac{4y+12}{16}=\frac{5z-25}{20}\)

\(=\frac{5z-25-3x+3-4y-12}{30-6-16}=\frac{\left(5z-3x-4y\right)+\left(-25+3-12\right)}{8}\)

\(=\frac{50-34}{8}=\frac{16}{8}=2\)

\(\Rightarrow\frac{x-1}{2}=2\Rightarrow x=5\)

\(\Rightarrow\frac{y+3}{4}=2\Rightarrow y=5\)

\(\Rightarrow\frac{z-5}{6}=2\Rightarrow z=17\)

2)

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

\(\Rightarrow4\left(2x-4x\right)=3\left(3x-2y\right)\Rightarrow8z-16x=9x-6y\Rightarrow25x-6y-8z=0\)

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

\(\Rightarrow3\left(4y-3z\right)=2\left(2z-4x\right)\Rightarrow12y-9z=4z-8x\Rightarrow8x+12y-13z=0\)

\(\Rightarrow2\left(25x-6y-8z\right)+8x+12y-13z=0\Rightarrow58x=29z\Rightarrow z=2x\)

\(8x+12y-13z=0\Rightarrow8x+12y-26x=0\Rightarrow12y=18x\Rightarrow y=\frac{3}{2}x\)

Theo đề ra, ta có: \(x+y-z=-10\Rightarrow x+\frac{3}{2}x-2x=-10\Rightarrow x=-20\)

\(\Rightarrow z=-40\)

\(\Rightarrow y=-30\)

\(\frac{7}{35}\div\left(x-\frac{1}{3}\right)=\frac{2}{25}\)

\(\left(x-\frac{1}{3}\right)=\frac{7}{35}\div\frac{2}{25}\)

\(x-\frac{1}{3}=\frac{7}{35}\times\frac{25}{2}\)

\(x-\frac{1}{3}=\frac{175}{70}\)

\(x=\frac{175}{70}+\frac{1}{3}\)

\(x=\frac{525}{210}\)

I don't know

Bài 1 góc còn lại = 100 độ

Bài 2 góc đối đỉnh xMz= 80 độ

         Các góc còn lại =100 độ