a) \(x^2\left(5x^3-x-\dfrac{1}{2}\right)\)
\(=5x^5-x^3-\dfrac{1}{2}x^2\)
b) \(\left(3xy-x^2+y\right)\dfrac{2}{3}x^2y\)
\(=2x^3y^2-\dfrac{2}{3}x^4y+\dfrac{2}{3}x^2y^2\)
c) \(\left(4x^3-5xy+2x\right)\left(-\dfrac{1}{2}xy\right)\)
\(=-2x^4y+\dfrac{5}{2}x^2y^2-x^2y\)
a.
\(x^2\left(5x^3-x-\dfrac{1}{2}\right)=x^2.5x^3-x^2.x-x^2.\dfrac{1}{2}\)
\(=5x^5-x^3-\dfrac{1}{2}x^2\)
b.
\(\left(3xy-x^2+y\right).\dfrac{2}{3}x^2y=3xy.\dfrac{2}{3}x^2y-x^2.\dfrac{2}{3}x^2y+y.\dfrac{2}{3}x^2y\)
\(=\dfrac{2}{3}x^3y^2-\dfrac{2}{3}x^4y+\dfrac{2}{3}x^2y^2\)
c.
\(\left(4x^3-5xy+2x\right).\left(-\dfrac{1}{2}xy\right)=4x^3.\left(-\dfrac{1}{2}xy\right)-5xy.\left(-\dfrac{1}{2}xy\right)+2x.\left(-\dfrac{1}{2}xy\right)\)
\(=-2x^4y+\dfrac{5}{2}x^2y^2-x^2y\)