a, \(\left(x-1\right)\left(x+1\right)\left(x+2\right)\)
\(=\left(x^2-1\right)\left(x+2\right)\)
\(=x^3-x+2x^2-1\)
b, \(\dfrac{1}{2}x^2y^2\left(2x+y\right)\left(2x-y\right)\)
\(=\dfrac{1}{2}x^2y^2\left(4x^2-y^2\right)\)
\(=2x^4y^2-\dfrac{1}{2}x^2y^4\)
( x - 1 ) ( x + 1 ) ( x + 2 ) = ( x2 - 1 ) ( x + 2 ) = x3 +x - 2
12x2y2(2x+y)(2x−y)" id="MathJax-Element-2-Frame" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline; float:none; font-size:18px; font-style:normal; font-weight:normal; letter-spacing:normal; line-height:normal; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:0px; position:relative; text-align:left; text-indent:0px; text-transform:none; white-space:nowrap; word-spacing:normal; word-wrap:normal" tabindex="0">12x2y2(2x+y)(2x−y) = 2x4y2 - 1/2x2y4
\(a,\left(x-1\right)\left(x+1\right)\left(x+2\right)=\left(x^2-1\right)\left(x+2\right)=x^3+2x^2-x-2\)\(b,\dfrac{1}{2}x^2y^2\left(2x+y\right)\left(2x-y\right)=\dfrac{1}{2}x^2y^2\left(4x^2-y^2\right)=2x^4y-\dfrac{1}{2}x^2y\)
