a) $(x-3)^{2}$= $x^{2}$- 2.3.x+ $x3^{2}$
=$x^{2}$- 6x+ 9
b) $($x^{2}$ +$y^{2}$ )^{2}$
=$($x^{2}$ )^{2}$+ $($y^{2}$ )^{2}$ +2.x.y
=$x^{4}$+ $y^{4}$+ 2xy
c) $($2x^{3}$- $3y^{2}$) ^{2}$
=$($2x^{3}$ )^{2}$+ $($3y^{2}$)^{2}$ - 2.$2x^{3}$.$3y^{2}$
=$4x^{6}$+ $9y^{4}$- 12$x^{3}$$y^{2}$
d) $($10x^{2}$- $3xy^{2}$ )^{2}$
=$($10x^{2}$)^{2}$+ $($3xy^{2}$)^{2}$- 2.$10x^{2}$.$3xyx^{2}$
=$100x^{4}$+ $9x^{2}$ $y^{4}$- 60$x^{3}$$x^{2}$ $y^{2}$
*Chúc bạn học tốt*
