100 - 9x^2 = (10 - 3x)(10 + 3x)c^2 - 8c + 16 = (c - 4)(c - 4) = (c - 4)^24a^2 + 20ab + 25b^2 = (2a + 5b)(2a + 5b) = (2a + 5b)^2
100 - 9x^2 = (10 - 3x)(10 + 3x)
c^2 - 8c + 16 = (c - 4)(c - 4) = (c - 4)^2
4a^2 + 20ab + 25b^2 = (2a + 5b)(2a + 5b) = (2a + 5b)^2