(a²+ab)÷(a²-b²)=?2.已知a²-4a+9b²+6b+5=0,求1/a-1/b的值 3.已知x²4.已知x+1/x=3,求x²÷(x四次方+x²+1)的值
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![(a²+ab)÷(a²-b²)=?2.已知a²-4a+9b²+6b+5=0,求1/a-1/b的值 3.已知x²4.已知x+1/x=3,求x²÷(x四次方+x²+1)的值](/uploads/image/z/1979577-9-7.jpg?t=%28a%26sup2%3B%2Bab%29%C3%B7%EF%BC%88a%26sup2%3B-b%26sup2%3B%EF%BC%89%3D%3F2.%E5%B7%B2%E7%9F%A5a%26sup2%3B-4a%2B9b%26sup2%3B%2B6b%2B5%3D0%2C%E6%B1%821%2Fa-1%2Fb%E7%9A%84%E5%80%BC+3.%E5%B7%B2%E7%9F%A5x%26sup2%3B4.%E5%B7%B2%E7%9F%A5x%2B1%2Fx%3D3%2C%E6%B1%82x%26sup2%3B%C3%B7%28x%E5%9B%9B%E6%AC%A1%E6%96%B9%2Bx%26sup2%3B%2B1%EF%BC%89%E7%9A%84%E5%80%BC)
(a²+ab)÷(a²-b²)=?2.已知a²-4a+9b²+6b+5=0,求1/a-1/b的值 3.已知x²4.已知x+1/x=3,求x²÷(x四次方+x²+1)的值
(a²+ab)÷(a²-b²)=?2.已知a²-4a+9b²+6b+5=0,求1/a-1/b的值 3.已知x²
4.已知x+1/x=3,求x²÷(x四次方+x²+1)的值
(a²+ab)÷(a²-b²)=?2.已知a²-4a+9b²+6b+5=0,求1/a-1/b的值 3.已知x²4.已知x+1/x=3,求x²÷(x四次方+x²+1)的值
(a²+ab)÷(a²-b²)
=a(a+b)÷[(a-b)(a+b)]
=a÷(a-b)
=a/(a+b)
.已知a²-4a+9b²+6b+5=0,求1/a-1/b的值
a²-4a+9b²+6b+5=0
a²-4a+4+9b²+6b+1=0
(a-2)²+(3b+1)²=0
(a-2)²=0,(3b+1)²=0
a=2,b=-1/3
1/a-1/b
=1/2-1/(-1/3)
=1/2+3
=7/2
3.已知x²
4.已知x+1/x=3,求x²÷(x四次方+x²+1)的值
x^2÷(x^4+x^2+1)取倒数
(x^4+x^2+1)÷x^2
=x^2+1+1/x^2
=x^2+2+1/x^2-1
=(x+1/x^2)^2-1
=3^2-1
=9-1
=8
再取倒数
x^2÷(x^4+x^2+1)=1/8
(a²+ab)÷(a²-b²)=a(a+b)/(a+b)(a-b)=a/(a-b)
由a²-4a+9b²+6b+5=0=(a-2)²+(3b+1)²=0从而得出a=2,b=-1/3,带入1/a-1/b=-3
求x²÷(x四次方+x²+1)可先求(x四次方+x²+1)*x²=...
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(a²+ab)÷(a²-b²)=a(a+b)/(a+b)(a-b)=a/(a-b)
由a²-4a+9b²+6b+5=0=(a-2)²+(3b+1)²=0从而得出a=2,b=-1/3,带入1/a-1/b=-3
求x²÷(x四次方+x²+1)可先求(x四次方+x²+1)*x²=x²+1+1/x²,由已知x+1/x=3推出x²+2+1/x²=3,进而得出x²+1+1/x²=2,从而x²÷(x四次方+x²+1)=1/((x四次方+x²+1)*x²)=1/(x²+1+1/x²)=1/2
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