1) y-8 - 3-4y = y(y-8) - 2(3-4y) = y²-8y-6+8y = y²-6
2y y² 2y² 2y² 2y²
2) 7 - 56 = 7 - 56 = 7(a+8)-56 = 7a+56-56 = 7a = 7
a a²+8a a a(a+8) a(a+8) a(a+8) a(a+8) a+8
3) b - b² = b - b² = b(b-1)-b² = b²-b-b² =
b+1 b²-1 b+1 (b+1)(b-1) (b+1)(b-1) b² -1
= -b = b
b² -1 1-b²
4) 3x - 15x² = 3x(5x+2) - 15x² = 15x² +6x -15x² = 6x
5x+2 5x+2 5x+2 5x+2