因式分解4x²-16和-x²y+4xy-5y

因式分解4x²-16和-x²y+4xy-5y
因式分解4x²-16和-x²y+4xy-5y

因式分解4x²-16和-x²y+4xy-5y
4x²-16
=4（x²-4）
=4(x+2)(x-2)
-x²y+4xy-5y
=-y(x²-4x+5)
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1. (2x+4)(2x-4)

2. y(-x²+4x-5)

4x²-16=4(x+2)*(x-2) -x²y+4xy-5y=-y((x-2)^2+1)

4x" - 16
= 4( x" - 4 )
= 4( x" - 2" )
= 4( x - 2 )( x + 2 )

-x"y + 4xy - 5y
= -y ( x" - 4x + 5 )