Question

已知函数:f(x)=x+a/x-6,d点(7,0)在该函数图像上.(1)求函数f(x)的表达式,(2)已知f(x)=2时

Answer 1

d点(7,0)在该函数图像上,

所以 7+a/7-6 = 0,a=-7

f(x) = x - 7/x - 6

f(x) = 2,

x - 7/x - 6 = 2

x^2 - 8x - 7 = 0

x = 4 + √23或者x=4 - √23