(1)3x²-4xy+6y²
Δ=4²-4×3×6=16-72<0,此题在实数范围内不能分解因式
题目有误?
(2)4x²+1/4-2x
=1/4(16x²-8x+1)
=1/4(4x-1)²
(3)(x²+x-1)(x²+x-4)+2
=(x²+x)²-5(x²+x)+4+2
=(x²+x)²-5(x²+x)+6
=(x²+x-2)(x²+x-3)
=(x+2)(x-1)(x²+x-3)
(1)=(3x-6y)^2+14xy
(2)=(4x-1/2)^2+2x
(3)=(x^2+x)(x^2+x-3)+6