Упражнение 642

Решение:

• $${\largeа)}\ (x-8)\cdot\frac{2}{5}=2$$$$\phantom{\largeа)}\ x-8=2:\frac{2}{5}$$$$\phantom{\largeа)}\ x-8=\cancel2^{\backslash1}\cdot\frac{5\phantom{0}}{\cancel2^{\backslash1}}$$$$\phantom{\largeа)}\ x-8=5$$$$\phantom{\largeа)}\ x=5+8$$$$\phantom{\largeа)}\ x=13$$
• $${\largeб)}\ 2\frac{1}{3}x-2\frac{1}{3}=2\frac{1}{3}$$$$\phantom{\largeб)}\ 2\frac{1}{3}\cdot(x-1)=2\frac{1}{3}$$$$\phantom{\largeб)}\ \frac{7}{3}\cdot(x-1)=\frac{7}{3}$$$$\phantom{\largeб)}\ x-1=\frac{7}{3}:\frac{7}{3}$$$$\phantom{\largeб)}\ x-1=\frac{\cancel7^{\backslash1}}{\cancel3^{\backslash1}}\cdot\frac{\cancel3^{\backslash1}}{\cancel7^{\backslash1}}$$$$\phantom{\largeб)}\ x-1=1$$$$\phantom{\largeб)}\ x=1+1$$$$\phantom{\largeб)}\ x=2$$