Question

 a)(y²x - 3ab)²

Answer 1

\(=y^4x^2-6y^2x\cdot ab+9a^2b^2\)

Answer 2

\(=\left(y^{^2}x\right)^2-6abxy^{^2}+\left(3ab\right)^{^2}\\ =y^{^4}x^{^2}-6abxy^{^2}+9a^{^2}b^{^2}\)

Answer 3

\(a.\left(y^2x-3ab\right)^2=\left(xy^2-3ab\right)^2=\left(xy^2\right)^2-2xy^2\cdot3ab+\left(3ab\right)^2\)

\(=x^2y^4-6xy^2ab+9a^2b^2.\)