Question

alpha and beta are roots of quadratic equation xsquare -7x+k =0 find value of k if alpha -beta =11

Answer 1

Xsq. -7x+k. Alpha - beta =11.....eq 1

Wkt, alpha +beta = -b/a

So, alpha + beta= -(-7)/1

i.e. alpha +beta=7. .........eq 2

Now eleminating the 2 eq. we get,

Alpha = 9 & beta= -2

Then wkt, alpha*beta = c/a

9 * -2 = -18 = c

-- Is it correct?