If 5√5x3 + 2√2y3 = (Ax + √2y)(Bx2 + 2y2 + Cxy), then the value of (A2 + B2 - C2) is:

Answer: Option B

$$\begin{array}{rl}& 5\sqrt{5}{x}^3+2\sqrt{2}{y}^3=\left(Ax+\sqrt{2}y\right)\left(B{x}^2+2y^2+Cxy\right)\\ & {\left(\sqrt{5}x\right)}^3+{\left(\sqrt{2}y\right)}^3=\left(\sqrt{5}x+\sqrt{3}y\right)\left(5x^2+9y^2-\sqrt{10}xy\right)\\ & \left(\sqrt{5}x+\sqrt{3}y\right)\left(5x^2+9y^2-\sqrt{10}xy\right)=\left(Ax+\sqrt{2}y\right)\left(B{x}^2+2y^2+Cxy\right)\\ & \text{Comparison both side:}\\ & A=\sqrt{5}\\ & B=5\\ & C=-\sqrt{10}\\ & A^2+B^2+C^2=5+25-10=20\end{array}$$