Question

if f(x) = 3x+a and f( 1) =7 find a and f(4) in answer​

Answer 1

F(1)=7
Then
We may write
F(1)= 3(1)+a=7

Then finally
a =7-3= 4
That’s why a = 4.

And by given questions
F(4) =3(4) +4
F(4) = 16

Answer 2

Answer:

Given,

f(x) = 3x+a

substituting x= 7 in f(x) we get,

f(1)= 7

3+a= 7

a= 4 -------------(I)

substituting x= 4 in f(x) we get,

f(4)= 3(4)+a

= 12+4 [from (I)]

= 16

therefore,

a= 4

f(4)= 16

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