1) 100 - 9x² = (10 - 3x)(10 + 3x)
2) 16m^8 - 25n⁴ = (4m^4 - 5n^2)(4m^4 + 5n^2)
3) 4a² + 20ab + 25b² = (2a + 5b)^2
4)49x²y - y³ = y(49x^2 - y^2) = y(7x - y)(7x + y)
5) -6m² + 12mn - 6n² = -6(m^2 - 2mn + n^2) = -6(m - n)^2
6) b³ - 8c³ = (b - 2c)(b^2 + 2bc + 4c^2)