先化简,再求值:(3⼀x-2+2⼀x+2)÷5x눀+2x⼀x눀-4,其中x=3

2024-12-27 03:34:15
推荐回答(1个)
回答1:

[3/(x-2)+2/(x+2)]÷(5x²+2x)/(x²-4)
=[3/(x-2)+2/(x+2)]*(x²-4)/(5x²+2x)
=[3/(x-2)+2/(x+2)]*(x-2)(x+2)/(5x²+2x)
=3/(x-2)*(x-2)(x+2)/(5x²+2x)+2/(x+2)*(x-2)(x+2)/(5x²+2x)
=3(x+2)/(5x²+2x)+2(x-2)/(5x²+2x)
=[3(x+2)+2(x-2)]/(5x²+2x)
=[3x+6+2x-4]/(5x²+2x)
=[5x+2]/[x(5x+2)]
=1/x
=1/3