If are the roots of the equation , and are the roots of the equation , find the value of
Note: Here and
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Applying sum of roots and product of roots,
a + b = 1 0 c ; c + d = 1 0 a - (i)
a b = − 1 1 d ; c d = − 1 1 b - (ii)
Adding both the equations in (i), we get a + b + c + d = 1 0 ( a + c ) → b + d = 9 ( a + c )
Equating the value of d b from (ii), we get a c = 1 2 1 . Now,
a 2 − 1 0 a c − 1 1 d = 0
c 2 − 1 0 a c − 1 1 b = 0
Adding both the equations above, we get,
( ( a + c ) 2 − 2 a c ) − 2 0 a c − 1 1 ( b + d ) = 0
Putting a + c = t , b + d = 9 t , a c = 1 2 1 , we get a quadratic equation in t .
( t − 1 2 1 ) ( t + 2 2 ) = 0 , t = 121, -22.
But, if we make t = − 2 2 , that would mean a + c = − 2 2 ; a c = 1 2 1 → a = c = − 1 1 , but that is not allowed.
Hence, a + c = 1 2 1
a + b + c + d = 1 0 ( a + c ) = 1 2 1 0