If the polynomial R(x) is the remainder upon dividing x2020 by x2−7x+12. If R(1) can be expressed as (pm−qn), where m,n∈N,andp&q are prime numbers, then the value of n+m−pq is
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Solution
Let R(x)=ax+b Then x2020=p(x2−7x+12)+R(x) ⇒x2020=(x−3)(x−4)f(x)+ax+b...(1)where f(x)is a polynomial function
Putting x=3 in equation 1 we get 32020=3a+b...(2)
Putting x=4 in equation 1 we get 42020=4a+b...(3)
From 2 and 3 we get a=42020−32020 b=4⋅32020−3⋅42020
R(1)=a+b ⇒42020−32020+4⋅32020−3⋅42020=32021−24041
equating it with the expression we get n+m−pq=4041+2020−6=6056