Question

if Alpha and beta are roots of x2 +5x + a and 2 alpha + 5 beta= -1 then value of a is​

Answer 1

Answer:

alpha + beta = -5 ..... (1)

and alpha×beta = a..... (2)

2alpha + 5beta = - 1....(3)

From (1) alpha = -5 - beta, put this value of alpha in (3)

2(-5-beta) +5beta = -1

-10 - 2beta + 5beta = -1

3beta = -1 + 10 = 9

beta = 9/3 = 3

put this value of beta in (1), you will get alpha = -8

Now a = alpha × beta = 3× (-8) = -24 Ans