初一关于因式分解的几道数学题(1).[(1/4)x^2 -x+1]/[1-(1/2)x]；(2).4(a-b)^2 -9a+9b .

[(1/4)x^2 -x+1]/[1-(1/2)x]；
=(x^2-4x+4)/(4-2x
＝（x-2)^2/[2(2-x)]
=(2-x)/2
4(a-b)^2 -9a+9b
=4(a-b)(a-b)-9(a-b)
=(a-b)(4a-4b-9)

[(1/4)x^2 -x+1]/[1-(1/2)x]
={[(1/2) 乘以x]^2 -2乘以(1/2)x乘以1+1}/[1-(1/2)x]
=[(1/2)x-1]^2 /[1-(1/2)x]
=-[1-(1/2)x]
=(1/2)x-1
4(a-b)^2 -9a+9b
=4(a-b)(a-b)-(9a-9b )
=4(a-b)(a-b)-9(a-b )
=(a-b)[4(a-b)-9]
=(a-b)(4a-4b-9]

[(1/4)x^2 -x+1]/[1-(1/2)x]；
=(x^2-4x+4)/(4-2x)(分子分目同时乘以4)
＝（x-2)^2/[2(2-x)]
=(2-x)/2
4(a-b)^2 -9a+9b
=4(a-b)(a-b)-9(a-b)
=(a-b)(4a-4b-9)

[(1/4)x^2 -x+1]/[1-(1/2)x]；
=((1-x/2)^2)/(1-x/2)
=1+x/2
4(a-b)^2 -9a+9b
=(a-b)4(a-b)-9(a-b)
=(a-b)(4a-4b-9)