pre calculus calculus f of x and g value

Question

If f(x) = 2x+1 and g(x) = (1/2)(x-1) what is the value of f (g(-4))?

Answer 1

If f(x) = 2x+1 and g(x) = (1/2)(x-1) what is the value of f (g(-4))

Start off by finding g(-4) by plugging -4 into the g(x) equation and simplifying

g(-4) = (1/2)(-4-1)

g(-4) = (1/2)(-5)

g(-4) = -5/2

Next, take this value and plug it into f(x) equation

f(-5/2) = 2(-5/2)+1

f(-5/2) = -5+1

f(-5/2) = -4

Answer 2

If f(x) = 2x+1 and g(x) = (1/2)(x-1) what is the value of f (g(-4))?

 

To determine f(g(x)), simply replace the x in f(x) with g(x):

 

f(x) = 2x + 1

 

f(g(x)) = 2g(x) + 1 = 2(1/2)(x-1) + 1

 

f(g(x)) = x - 1 + 1 = x

 

f(g(x=-4)) = -4