[(x+2y)²-(x-2y)²-(x+2y)(x-2y)-4y²]÷2,其中x=-2,y=½怎么算要过程,算得快有加分
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[(x+2y)²-(x-2y)²-(x+2y)(x-2y)-4y²]÷2,其中x=-2,y=½怎么算要过程,算得快有加分
[(x+2y)²-(x-2y)²-(x+2y)(x-2y)-4y²]÷2,其中x=-2,y=½怎么算要过程,算得快有加分
[(x+2y)²-(x-2y)²-(x+2y)(x-2y)-4y²]÷2,其中x=-2,y=½怎么算要过程,算得快有加分
[(x+2y)²-(x-2y)²-(x+2y)(x-2y)-4y²]÷2
=【(x+2y+x-2y)(x+2y-x+2y)-(x²-4y²)-4y²】÷2
=【8xy-x²】÷2
因为
x=-2,y=½
所以原式=【8*(-2)*½ - 4】÷2=-6
1.原式={(x+2y+x-2y)[x+2y-(x-2y)]-[x²-(2y)²]-4y²}]÷2x
=(8xy-x²)÷2x=4y-x÷2=3
2.打开括号得:2x²-5x+6x-15-(2x²-16x+x-8)=41
...
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1.原式={(x+2y+x-2y)[x+2y-(x-2y)]-[x²-(2y)²]-4y²}]÷2x
=(8xy-x²)÷2x=4y-x÷2=3
2.打开括号得:2x²-5x+6x-15-(2x²-16x+x-8)=41
16x=48
x=3
3.原式=3的m次方×3的2m次方×3的3m次方×3的4m次方=3的10m次方=3的30次方,由此可得m=3
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[(x+2y)²-(x-2y)²-(x+2y)(x-2y)-4y²]÷2
=(x²+4y²+4xy-x²-4y²+4xy-x²+4y²-4y²)÷2
=(8xy-x²)÷2
=-6
[(x+2y)²-(x-2y)²-(x+2y)(x-2y)-4y²]÷2
=【(x+2y+x-2y)(x+2y-x+2y)-(x²-4y²)-4y²】÷2
=(2x*4y-x²+4y²-4y²)÷2
=(8xy-x²)÷2;
x=-2,y=½代入:
(...
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[(x+2y)²-(x-2y)²-(x+2y)(x-2y)-4y²]÷2
=【(x+2y+x-2y)(x+2y-x+2y)-(x²-4y²)-4y²】÷2
=(2x*4y-x²+4y²-4y²)÷2
=(8xy-x²)÷2;
x=-2,y=½代入:
(8xy-x²)÷2;
=(8×(-2)×½-(-2)²)÷2;
=(-8-4)÷2
=-6
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