Question

Thank difference of two no. Is 4 and their difference of the receprocal is 4/21 find the no.

Answer 1

Hello Arghya
Let the no.s be x and y. and x>y
Then according to question
x-y=4. (1)
and
1/y-1/x=4/21
or,x-y/xy=4/21
or,4/xy=4/21
or,xy=21
or,y=21/x
putting y=21/x in equation 1 we get
x-21/x=4
or,(x²-21)/x=4
or,x²-21=4x
or,x²-4x-21=0
or,x²-7x+3x-21=0
or,x(x-7)+3(x-7)=0
or,(x-7)(x+3)=0
or,x=7 or x=-3
as x-y=4
or,y=x-4
=7-4=3. when x=7
or-3-4=-7. when x=-3
x=7,y=3 and,x=-3,y=-7
Hope it helps.

Answer 2

7 and 3 are the two numbers