1) 12х^9 y^5/18x y6 = 2x⁸ * 3y
2) 5a - 15/10a = 5(a-3) \ 10a = a-3 \ 2a
3)m^2 - n^2/m+n = (m-n)(m+n) \ (m+n) = m-n
4)m^2-1/1+m = (m-1)(m+1) \ 1+m = m-1
5)m^2-1/m^2-2m+1 = (m-1)(m+1)\(m-1)² = m+1 \ m-1
6)x^2-8x+16/x^2-16 = (x-4)² \ (x-4)(x+4) = x-4 \ x+4