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解条件式求值问题要认真分析条件式和待求式,寻求合理的解题方法,下面结合实例介绍几种常用的求解方法.1.求值代入利用已知条件,求出未知数的值,然后代入分式中,求出分式的值.例1已知x~2+y~2-8x+10y+41=0.求x/y-y/x的值.解因为x~2+y~2-8x+10y+41=0,所以(x-4)~2+(y+5)~2=0,
Solving the conditional expression problem should be carefully analyzed conditional and to be sought-after, to find a reasonable solution to the problem, the following combination of examples to introduce several commonly used method of solution.1.Using known conditions to obtain the known conditions, to find the value of the unknown, And then substituted into the fractional, find the fractional value .Example 1 Known x ~ 2 + y ~ 2-8x + 10y + 41 = 0. Find x / yy / x value of the solution. Because x ~ 2 + y ~ 2-8x + 10y + 41 = 0, so (x-4) ~ 2 + (y + 5) ~ 2 = 0,