Find the value of k for which the roots a, b of the equation
x^2 - 6x + k = 0 satisfy the relation 2a + 3b = 20.
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Answer:
Step-by-step explanation:
P(x)=x²-6x+k
And 'a' and 'b' are the roots
So, a+b=-(coefficient of x)/(coefficient of x²)
or a+b=-(-6)/1
or a+b=6 eq. (1)
It is given that
2a+3b=20 eq.(2)
Multiplying eq.(1) by 2 we get,
2a+2b=12 eq.(3)
Subtracting (3) from (2) we get
2a+3b-2a-2b=20-12
b=8
Putting b=8 in (1)
a+8=6
a=6-8
a=-2
Now,
ab = constant term/coefficient of x²
8×-2=k/1
-16=k
K=-16
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