f(x+y)=f(x)f(y) with f(1)=7 gives f(x)=7x.
For g: put y=1 in g(x+y)=g(xy) to get g(x+1)=g(x).
So g(x)=g(1)=1 for all x∈N.
x=1∑ng(x)f(x)=x=1∑n7x=67(7n−1)=19607
7n+1−7=117642
⇒7n+1=117649=76
n+1=6⇒n=5
JEE Main 2026 — Mathematics Algebra
Let f and g be functions satisfying f(x+y)=f(x)f(y),f(1)=7 and g(x+y)=g(xy),g(1)=1, for all x,y∈N. If x=1∑n(g(x)f(x))=19607, then n is equal to:
Held on 22 Jan 2026 · Verified 6 Jul 2026.
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