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计算 4x^2/2x-3+9/3-2x 12/m^2-9-2/m-3 2x^2/3y^2乘以5y/6x除以10y/21x

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计算 4x^2/2x-3+9/3-2x 12/m^2-9-2/m-3 2x^2/3y^2乘以5y/6x除以10y/21x^2 a^2-ab/a^2除以(a/b-b...
计算 4x^2/2x-3+9/3-2x 12/m^2-9-2/m-3 2x^2/3y^2乘以5y/6x除以10y/21x^2 a^2-ab/a^2除以(a/b-b/a) 急阿! 求你高手阿 要过程呢
4x^2/(2x-3)+9/(3-2x)
=4x^2/(2x-3)-9/(2x-3)
=(4x^2-9)/(2x-3)
=(2x+3)(2x-3)/(2x-3)
=2x+3
12/(m^2-9)-2/(m-3)
=12/(m-3)(m+3)-2(m+3)/(m-3)(m+3)
=[12-2(m+3)]/(m-3)(m+3)
=(12-2m-6)/(m-3)(m+3)
=(6-2m)/(m-3)(m+3)
=-2(m-3)/(m-3)(m+3)
=-2/(m+3)
2x^2/3y^2*5y/6x÷10y/21x^2
=2x^2/3y^2*5y/6x*21x^2/10y
=2/3*5/6*21/10*x^(2-1+2)y^(-2+1-1)
=7/6*x^(-1)y^(-2)
=7/(6xy^2)
(a^2-ab)/a^2÷(a/b-b/a)
=a(a-b)/a^2÷(a^2/ab-b^2/ab)
=(a-b)/a÷[(a^2-b^2)/ab]
=(a-b)/a*ab/(a^2-b^2)
=(a-b)/a*ab/(a-b)(a+b)
=b/(a+b)