Đáp án:
Giải thích các bước giải:
a). 3 (x - y) - 5xy (y - x)
= 3 (x - y) + 5xy (x - y)
= (3 + 5xy) (x - y)
b). $\frac{2}{5}$x (y - 1) + $\frac{2}{5}$ y (1 - y)
= $\frac{2}{5}$x (y - 1) - $\frac{2}{5}$y (y - 1)
= $\frac{2}{5}$ (y - 1) (x - y)
c). x (x - 1) - y (1 - x)
= x (x - 1 ) + y (x - 1)
= (x + y) (x - 1)
d). 7x (5x - y) + 2 (5x - y) - 3y (y - 5x)
= 7x (5x - y) + 2 (5x - y) + 3y (5x - y)
= (7x + 2 + 3y) (5x - y)
e). 2y (3 - x) + 3xy (x - 3)
= 2y (3 - x) - 3xy (x + 3)
= (2y - 3xy) (3 - x)
= y (2 - 3x) (3 - x)
