1. (x^2+b)(x^2+2b) 2. (y^2+c)(y^2+3c) 3. (2m+n^2)(2n-m^2) 4. (2a+b^2)(2b-a^2) 5. (n+2m)(n-2m) 6. (b+2a)(b-2a)

(x² + b)(x² + 2b) = x^4 + 3bx² +2b²
(y² + c)(y² + 3c) = y^4 + 4cy² + 3c²
(2m + n²)(2n - m²) = 4mn - 2m^3 + 2n^3 - n²m²
(2a + b²)(2b - a²) = 4ab - 2a^3 + 2b^3 - b²a²
(n + 2m)(n + 2m) = n² + 4mn + 4m²
(b + 2a)(b - 2a) = b² - 4a²