a) Ta có: \(3x\left(y^2-2z\right)-\left(x-4\right)\left(2z-y^2\right)\)
\(=3x\left(y^2-2z\right)+\left(x-4\right)\left(y^2-2z\right)\)
\(=\left(y^2-2z\right)\left(3x+x-4\right)\)
\(=4\left(x-1\right)\left(y^2-2z\right)\)
b) Ta có: \(6y^2\left(5-x\right)^3-15y\left(x-5\right)^2\)
\(=-6y^2\left(x-5\right)^3-15y\left(x-5\right)^2\)
\(=-3y\left(x-5\right)^2\cdot\left[2y\left(x-5\right)-3\right]\)
\(=-3y\left(x-5\right)^2\cdot\left(2xy-10y-3\right)\)
c) Ta có: \(\left(a+2c\right)\left(3a^2+5a^2b\right)-\left(7a^2-3a^2b\right)\cdot\left(a+2c\right)\)
\(=\left(a+2c\right)\left(3a^2+5a^2b-7a^2+3a^2b\right)\)
\(=\left(a+2c\right)\left(8a^2b-4a^2\right)\)
\(=4a^2\left(a+2c\right)\left(2b-1\right)\)
a.\(3x\cdot\left(y^2-2z\right)-\left(x-4\right)\cdot\left(2z-y^2\right)\)
\(3x\cdot\left(y^2-2z\right)-\left(x-4\right)\cdot\left(-\left(y^2-2z\right)\right)\)
\(3x\cdot\left(y^2-2z\right)+\left(x-4\right)\cdot\left(y^2-2z\right)\)
\(\left(y^2-2z\right)\cdot\left(3x+x-4\right)\)
\(\left(y^2-2z\right)\cdot4\left(x-1\right)\)
\(4\left(y^2-2z\right)\cdot\left(x-1\right)\)
