Question

4x^4+3x^2+1因式分解

Answer 1

令x^2=t
则原式=4t^2+3t+1
由十字相乘法,得
=（t+1)(4-t)
再令t=x^2
原式=(x^2+1)(4-x^2)
平方差公式,得
=(x^2+1)(2+x)(2-x)