1 / t (5t +3)

2 / (2x + 1) [ (2x+1) - 4] = (2x + 1) (2x + 1 - 4) = (2x + 1) (2x - 3)

3 / (a -3 ) (a + 3)

4 / (x+2 -3) (x+2 +3) = (x-1) (x+5)

5 / (x +8) au carré