3(X-7.8)=36.9解:x-7.8=36.9除3x-7.8=12.3x-7.8+7.8=12.3+7.8x=20.1
三括号x-7点八括号=36点九方程解3(x-7.8)=36.9,3x-23.4=36.9,3x=36.9+23.4,3x=60.3,x=20.1.
3(x-7.8)=36.9x-7.8=12.3x=20.1
方程两边同时除以3x=20.1