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Solution


Q.

If x = –2 and 3/4 are the roots of the quadratic equation Ax² + Bx – 6 = 0, based on this what can you say about the nature of values A and B

(i) Both are positive numbers.
(ii) One is positive and the other is negative.
(iii) Both are odd.
(iv) Sum of A and B is an odd number.

 

Choose the correct option from the following
1 Only (ii) and (iii) are correct  
2 Only (i) and (ii) are correct  
3 Only (i) and (iv) are correct  
4 Only (iii) and (iv) are correct  

Ans.

(3)

Given, x = –2 and 3/4 are roots of the quadratic equation Ax² + Bx – 6 = 0.

Product of roots = –6/A  ⇒  (–2 × 3/4) = –6/A  ⇒  A = 4
Sum of roots = –B/A  ⇒  (–2 + 3/4) = –B/4  ⇒  –5/4 = –B/4  ⇒  B = 5

Both A and B are positive numbers and sum of A and B is an odd number.