e)
pr · 3p - r - (- rp) · (- 2pr) + 3 · prprp - r · 4pp = 3p²r - r - 2p²r² + 3p³r³ - 4p²r =
= 3p³r³ - 2p²r² - p²r - r
f)
[tex]2x:(-5x)y -7:(-3xy) + 2xy - 3x -(-4xy) (-2) = -\frac{2x}{5x}y + \frac{7}{3xy} +2xy - 3x -8xy = \\\\ = - 6xy - 3x -\frac{2}{5}y + \frac{7}{3xy}[/tex]
