Question

Thu gọn các đa thức sau:

a) \(3xyz^2+\left(\frac{-4}{8}xyz^5\right)\text{ nhân}\frac{1}{3}xyz\)

b) \(3xyz^5\text{nhân}\left(\frac{-1}{7}xyz^2\right)\text{nhân}\frac{-1}{8}xyz^4\)

Answer 1

\(3xyz^2+\left(-\frac{4}{8}\right)xyz^5\cdot\frac{1}{3}xyz\)

\(=3xyz^2-\frac{1}{2}xyz\cdot\frac{1}{3}xyz\)

\(=3xyz-\frac{1}{6}x^2y^2z^2\)

\(xyz\left(3-\frac{1}{6}xyz\right)\)

b) \(3xyz^5\cdot\left(-\frac{1}{7}\right)xyz\cdot\frac{-1}{8}xyz^4\)

\(=\left[3\cdot\left(-\frac{1}{7}\right)\cdot\left(-\frac{1}{8}\right)\right]\left(x\cdot x\cdot x\right)\left(y\cdot y\cdot y\right)\left(z^5\cdot z\cdot z^4\right)\)

\(=\frac{3}{56}x^3y^3z^{10}\)

Answer 2

a, \(3xyz^2+\left(\frac{-4}{8}xyz^5\right)\cdot\frac{1}{3}xyz=3xyz^2+\left[\left(\frac{-4}{8}\right)\cdot\frac{1}{3}\right]xyz^5xyz\)\(=3xyz^2-\frac{1}{2}x^2y^2z^6\)

b, \(3xyz^5\cdot\left(\frac{-1}{7}xyz^2\right)\cdot\frac{-1}{8}xyz^4=\left[3\cdot\left(\frac{-1}{7}\right)\cdot\left(\frac{-1}{8}\right)\right]xyz^5xyz^2xyz^4=\frac{3}{56}x^3y^3z^{11}\)