已知a^2+b^2-6a-8b+25=0,试求代数式(1+b/a-a/a-b)/(1-b/a-a/a+b)的值.
问题描述:
已知a^2+b^2-6a-8b+25=0,试求代数式(1+b/a-a/a-b)/(1-b/a-a/a+b)的值.
答
因为a^2+b^2-6a-8b+25=0,
所以(a^2-6a+9)+(b^2-8b+16)=0
(a-3)²+(b-4)²=0
所以a=3,b=4
将a=3,b=4带入(1+b/a-a/a-b)/(1-b/a-a/a+b)得
(1+4/3-1-4)/(1-4/3-1+4)
=(-8/3)/(8/3)
=-8/3*3/8
=-1
答
∵a²+b²-6a-8b+25=0
∴(a²-6a+9)+(b²-8b+16)=0
∴(a-3)²+(b-4)²=0
∴a=3,b=4
(1+b/a-a/a-b)/(1-b/a-a/a+b)
=(1+4/3-3/3-4)/(1-4/3-3/3+4)
=(5/3 +3)/(-1- 3/7)
=14/3 × (-7)/10
=-49/15
答
等式a^2+b^2-6a-8b+25=0可化为:a²-6a+9+b²-8b+16=0(a-3)²+(b-4)²=0则可得:a-3=0,b-4=0即:a=3,b=4所以:[1+ b/a - a/(a-b)] /[1 - b/a - a/(a+b)]=[(a+b)/a - a/(a-b)]/[(a-b)/a - a/(a+b)]=(...