dxmrose
幼苗
共回答了15个问题采纳率:93.3% 举报
(1)3a-3b/10ab · 25a^2b^3/a^2-b^2
=3(a-b)/10ab· 25ab(ab^2)/(a+b)(a-b)
=3(a-b)/2*5ab· 5*5ab(ab^2)/(a+b)(a-b)
=3*5(ab^2)/2(a+b)
=15ab^2/2a+2b
(2)(x²-4y²)/(x²+2xy+y²)÷(x+2y)/(2x²+2xy)
=[(x-2y)*(X+2Y)]/(X+Y)^2 ÷(x+2y)/[2x*(x+y)]
=[(x-2y)*(X+2Y)]/(X+Y)^2*[2x*(x+y)]/(X+2Y)
=(X-2Y)*2X/(X+Y)
(3)=(a+b)²(a-b)²/b²÷[a³(a+b)³]×a²b²/(b-a)²
=(a+b)²(a-b)²/b²×1/[a³(a+b)³]×a²b²/(b-a)²
=1/[a(a+b)]
=1/(a²+ab)
=1/9
(4)=(m+4)(m-4)/[-3(m-4)]×1/m(m+4)
=-1/3m
1年前
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