A) Ta có: \(24\cdot\left(13-7\right)-13\left(24-7\right)\)
\(=24\cdot13-24\cdot7-13\cdot24+13\cdot7\)
\(=7\left(-24+13\right)=7\cdot\left(-11\right)=-77\)
B) Ta có: \(5\cdot\left(-3\right)^2\cdot\left(-1\right)^3+\left(-2020\right)^0\)
\(=5\cdot9\cdot\left(-1\right)+1\)
\(=-45+1=-44\)
C) Ta có: \(18\cdot\left(-45\right)-2\cdot9\cdot5\)
\(=-18\cdot45-2\cdot45\)
\(=45\cdot\left(-18-2\right)=45\cdot\left(-20\right)=-900\)