1.(16y^4-9x^4)/(-3x^2-4y^2) 2.(-2x+y)(-2x-y)

1.(16y^4-9x^4)/(-3x^2-4y^2) 2.(-2x+y)(-2x-y)
1.(16y^4-9x^4)/(-3x^2-4y^2) 2.(-2x+y)(-2x-y)

1.(16y^4-9x^4)/(-3x^2-4y^2) 2.(-2x+y)(-2x-y)
(16y^4-9x^4)/(-3x^2-4y^2)
=(4y²+3x²)(4y²-3x²)/-(3x²+4y²)
=3x²-4y²
(-2x+y)(-2x-y)
=-(y-2x)(y+2x)
=4x²-y²

1. (16y^4-9x^4)/(-3x^2-4y^2)=(4y²+3x²)(4y²-3x²)/-(3x^2+4y^2)=-(4y²-3x²)=3x²-4y²
2.(-2x+y)(-2x-y)=(2x-y)(2x+y)=4x²-y²

(16y^4-9x^4)/(-3x^2-4y^2)=（4y^2+3x^2)(4y^2-3x^2)/(-3x^2-4y^2)=3x^2-4y^2
(-2x+y)(-2x-y)=4x^2-y^2
都是利用平方差公式

(16y^4-9x^4)/(-3x^2-4y^2)
=(4y²+3x²)(4y²-3x²)/[-(3x²+4y²)]
=-(4y²-3x²)
=3x²-4y²
2.(-2x+y)(-2x-y)=4x²+2xy-2xy-y²=4x²-y²