Question

Let f(x)=-5x+3 and g(x)=6x-2. Find f •g and it's domain.

Answer 1

For this case what you should do is the composition of functions.
f • g = f (g (x)) = - 5 (6x-2) +3
Rewriting the function we have
f (g (x)) = - 30x + 13
Then, the domain of the function will be that for which the function is defined. In this case, the function is defined for all reals, or equivalently:
x = (- inf, inf)
answer
f (g (x)) = - 30x + 13
x = (- inf, inf)

Answer 2

f(x)= -5x+3; g(x)=6x-2. f.g = (-5x+3) x (6x-2) = â’30x^2 + 10x + 18x â’ 6 = â’30x^2 + 28x â’ 6 Domain is the set of values that the expression is defined or satisfied. => â’30x^2 + 28x â’ 6 = 0 For the above expression, the domain is real numbers. So x belongs to R.