x的平方+x分之2-x 除以 x的平方+2x+1分之x的平方-3x *4-2x分之9-x的平方

(2-x)/(x^2+x)÷(x^2-3x)/(x^2+2x+1)*(9-x^2)/(4-2x)
=(2-x)/(x^2+x)*(x^2+2x+1)/(x^2-3x)*(9-x^2)/(4-2x)
=(2-x)/(x^2+x)*(9-x^2)/(4-2x)*(x^2+2x+1)/(x^2-3x)
=(2-x)/(x^2+x)*(9-x^2)/2(2-x)*(x^2+2x+1)/(x^2-3x)
=1/(x^2+x)*(9-x^2)/2*(x^2+2x+1)/(x^2-3x)
=1/x(x+1)*(3-x)(3+x)/2*(x+1)^2/x(x-3)
=1/x*(3-x)(3+x)/2*(x+1)/x(x-3)
=-1/x*(x-3)(3+x)/2*(x+1)/x(x-3)
=-1/x*(3+x)/2*(x+1)/x
=-(3+x)(x+1)/2x^2