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Question
If `x = 2` is a root of the polynomial `f(x) = 2x2 – 3x + 7a` find the value of a.
Solution
We have f(x) = 2x2 – 3x + 7a
put `x=2⇒ f(2)=2(2)^2-3(2)+7a`
`=2xx4-3xx2+7a=8-6+7`
`=2+7a`
given `x=2` is a root of `f(x)=2x^2-3x=7a`
`⇒f(2)=0`
`∴2+7a=0`
`⇒7a=-2⇒ a=-2/7`
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