\(17.\left(\dfrac{5}{17}-\dfrac{1}{34}+\dfrac{1}{2}\right)\\ =\dfrac{17.5}{17}-\dfrac{17}{34}+\dfrac{17}{2}\\ =5-\dfrac{1}{2}+\dfrac{17}{2}\\ =\dfrac{9}{2}+\dfrac{17}{2}\\ =\dfrac{26}{2}=13\)

\(20,21\times35,75+20,21\times62,25+40,42\\ =20,21\times35,75+20,21\times62,25+20,21\times2\\ =20,21\times\left(35,75+62,25+2\right)\\ =20,21\times100\\ =2021\)

4+(-3)=1

tau biết ròi:)

Diện tích phải sơn là:

\(1,2\times1,2\times5\times2=14,4\left(m^2\right)\)

con công