Chiều rộng : `45xx1/3=15(cm)`

`C=(45+15)xx2=120(cm)`

\((x+1)(x+2)-(x-3)-(x+4)=6\)

\(\Leftrightarrow x^2 +3x+2-x^2-x+12=6\)

\(\Leftrightarrow 2x=-8\)

\(\Leftrightarrow x=-4\)

:vv Nhầm môn r cou

\(=\left(12,3+34,7\right)+\left(54,6+15,4\right)+\left(14,2+23,8\right)\\ =47+70+38\\ =155\)