1) (x+4)(x+4) = x^2 + 4x + 4x + 16 = x^2 + 8x + 16
2) (y-5x)(y-5x) = y^2 - 5xy - 5xy + 25x^2 = y^2 - 10xy + 25x^2
3) (3a-2)(3a+2) = 9a^2 - 6a + 6a - 4 = 9a^2 - 4
1) (x+4)(x+4) = x^2 + 4x + 4x + 16 = x^2 + 8x + 16
2) (y-5x)(y-5x) = y^2 - 5xy - 5xy + 25x^2 = y^2 - 10xy + 25x^2
3) (3a-2)(3a+2) = 9a^2 - 6a + 6a - 4 = 9a^2 - 4