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                                    Which of the following equations has no real roots?A. `x^(2)-4x+3sqrt(2)=0`B. `x^(2)+4x-3sqrt(2)=0`C. `x^(2)-4x-3sqrt(2)=0`D. `3x^(2)+4sqrt(3)x+4=0` | 
                            
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Answer» (a) The given equation is `x^(2)-4x+3sqrt(2)=0` On comparing with `ax^(2)+bx+c=0`, we get `a=1,b=-4` and `c=3sqrt(2)` The discriminant of `x^(2)-4x+3sqrt(2)=0` is `D=b^(2)-4ac` `=(-4)^(2)-4(1)(3sqrt(2))=16-sqrt(2)=16-12xx(1.41)` `=16-16.92=-0.92` `implies b^(2)-4aclt0` (b) The given equation is `x^(2)+4x-3sqrt(2)=0` On comparing the equation with `ax^(2)+bx+c=0` we get `a=1,b=4` and `c=-3sqrt(2)` Then `D=b^(2)-4ac=(-4)^(2)-4(1)(-3sqrt(2))` `=16+12sqrt(2)gt0` Hence the equation has real roots. (c) Given equation is `x^(2)-4x-3sqrt(2)=0` On comparing the equation with `ax^(2)+bx+c=0` we get `a=1,b=-4` and `c=-3sqrt(2)` Then `D=b^(2)-4ac=(-4)^(2)-4(1)(-2sqrt(2))` `=16+12sqrt(2)gt0` Hence, the equation has real roots. (d) Given equation is `3x^(2)+4sqrt(3)x+4=0` On comparing the equation with `ax^(2)+bx+c=0` we get `a=3,b=4sqrt(3)` and `c=4` Then `D=b^(2)-4ac=(4sqrt(3))^(2)-4(3)(4)=48-48=0` Hence, the equation has real roots. Hence `x^(2)-4x+3sqrt(2)=0` has no real roots.  | 
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