1)
а) (15a(a-b)) / (40b(a-b)) = 15a/40b = 3a / 8b
б) (y^2 + y) / y^2 = (y (y+1)) / y^2 = (y+1) / y
2)
a) (12x-7) / 15x + (3x-2) / 15x =
= (12x - 7 + 3x - 2) / 15x = (15x - 9) / 15x =
= 1 - 9/15x = 1 - 3 / 5x
б) ((ax + ay) / xy^2) * (x^2*y / (3x + 3y))=
= (a(x + y) * x^2 * y) / (x * y^2 * 3(x+y))=
= ax / 3y