Question

Answer 1

a: \(A=\left(-\frac57x^3yz\right)\cdot\left(\frac{14}{15}xy^2\right)\cdot\left(-\frac12xz\right)^2\)

\(=-\frac57\cdot\frac{14}{15}\cdot\frac14\cdot\left(x^3\cdot x\cdot x^2\right)\cdot\left(y\cdot y^2\right)\cdot z\cdot z^2=\frac{-70}{420}x^6y^3z^3\)

\(=-\frac16x^6y^3z^3\)

Bậc là 6+3+3=12

b: \(B\left(x\right)=-x^3+x^2-5x-4+x^2+x^3+9\)

\(=\left(-x^3+x^3\right)+x^2+x^2-5x+\left(-4+9\right)\)

\(=2x^2-5x+5\)