Question

If α and β are zeroes of x2 + 7x +12, then find the value of 1/a + 1/b-2ab pls answer guys humble request for this question the solution is correct or no pls do not spam

Let alpha =a , beta =b.

a and b are the zeroes of x^2+7x+12 =0.

a+b = -7…………..(1)

a.b= 12……………..(2)

Now 1/a+1/b +2.ab =?

=(b+a)/ab +2.ab

= -7/12 +2×12

=-7/12 +24

=(-7 +288)/12

= 281/12 or 23 5/12 , Answer

Answer 1

It is correct. There's no need to write the last value in mixed form. (:

Tip: If we have to find the value of α - β in any quadratic polynomial p(x) in the form of ax^2 + bx + c, then, $\alpha - \beta = \dfrac{\sqrt{b^2 - 4ac}}{a}$.