If 2 and 3 are the roots of the polynomial 3x^2 - 2kx + 2m=0 then find the value of M
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Since 2 and 3 are the roots, we have
( x − 2 ) ( x − 3 ) = 0
x 2 − 3 x − 2 x + 6 = 0
x 2 − 5 x + 6 = 0
Multiplying it by 3 , gives
3 x 2 − 1 5 x + 1 8 = 0
So,
2 m = 1 8
It follows that,
m = 9
If 2 , 3 are the roots then we can put x = 2 , 3 and the equation will be equal to 0 .We get 2 equations: 3 ( 2 ) 2 − 2 k ( 2 ) + 2 m = 0 → ( a f t e r s i m p l i f i c a t i o n ) 2 k − m = 6 3 ( 3 ) 2 − 2 k ( 3 ) + 2 m = 0 → ( a f t e r s i m p l i f i c a t i o n ) 6 k − 2 m = 2 7 m = 2 k − 6 .Substituting this into the second equation and simplifying,we get k = 7 . 5 .Substituting this into the first equation gives us m = 9
subtract both the equations to get the value of k=7.5...
then substitute 'k' in both equations to get M=9.
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By Vieta's formula, product of the roots is 2m/3 = 6 which gives us m = 9 on cross-multiplication.