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Question
Find the values of a and b when the polynomials f(x)= 2x2 -5x +a and g(x)= 2x2 + 5x +b both have a factor (2x+1).
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Solution
(2x + 1) ⇒ x = `-1/2`
Solving equation (i), we get
`"f"(-1/2) = 2 xx (-1/2) xx (-1/2) - 5 xx (-1/2) + "a" = 0`
`=> 1/2 + 5/2 + "a" = 0`
⇒ a = -3
`"g" (-1/2) = 2 xx (-1/2) xx (-1/2) + 5 xx (-1/2) + "b" = 0`
`=> 1/2 - 5/2 + "b" = 0`
⇒ b = 2
⇒ a = -3 , b = 2
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