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If for all real values of a one root of the equation `x^2-3ax + f(a)=0` is double of the other, then f(x) is equal toA. `2x`B. `x^(2)`C. `2x^(2)`D. `2sqrt(x)` |
Answer» Correct Answer - C Let `alpha` beone of `x^(2)-3ax+f(a)=0` `impliesalpha+2alpha=3alphaimplies3alpha=3a` `impliesalpha=a` …………i and `alpha.2alpha=f(a)` `impliesf(a)=2alpha^(2)=2alpha^(2)` [ using Eq. (i)] `impliesf(x)=2x^(2)` |
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