(2x^2 + 3x + 5)^2 = 4x^4 + 6x^3 + 10x^2 + 6x^3 + 9x^2 + 15x + 10x^2 + 15x + 25
= 4x^4 + 12x^3 + 19x^2 + 30x + 25.