1.

If b is the harmonic mean of a and c and `alpha, beta` are the roots of the equation `a(b-c)x^(2) + b(c-a) x+ c(a-b)=0`, thenA. `alpha + beta = 3`B. `alpha+beta=(1)/(2)`C. `alpha beta = 2`D. `alpha = 1, beta = 1`

Answer» Correct Answer - D
We observe that the sum of the coefficients of the given equation is zero. Therefore, 1 is a root of the given equation.
Let `alpha = 1 and beta` be the other root. Then,
`beta xx 1 =(c(a-b))/(a(b-c))rArr beta = (c)/(a) xx {(a-(2ac)/(a+c))/((2ac)/(a+c)-c)}=1" "[because b = (2ac)/(a+c)]`
Hence, `alpha = beta = 1`


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