（1）a²+（2b-3）a+b²-3b+2
=a²+2ab-3a+b²-3b+2
=a²+2ab+b²-3a-3b+2
=(a+b)²-3(a+b)+2
=(a+b-2)(a+b-1)
（2）9^n - 3^(n+2)- 10
=(3^2)^n - 3^2*3^n- 10
=3^2n-9*3^n-10
=(3^n-10)(3^n+1)
x^4 - 3x^2 + 1
=x^4 - 2x^2 + 1 -x^2
=(x^2-1)^2-x^2
=(x^2-1-x)(x^2-1+x)