Question

we have : f(x) = 10x
Prove that : f(a + b) = f(a) + f(b)

Answer 1

Given:

f(x)=10x

So:

f(a+b)=10(a+b)

==) f(a+b)=10a+10b...............(1)

f(a)=10a............(2)

f(b)=10b................(3)

Adding 2 and 3 gives

f(a)+f(b)=10a+10b

==)f(a)+f(b)=f(a+b)[from (1)]

Hence proved

Hope it helps.