Composite Function Calculator
Evaluate f(g(x)) for two linear functions.
Enter your values
ⓘ Live results
Results
- f(g(x))
- 21
- g(x)
- 10
- g(f(x))
- 25
- f(x)
- 9
Quick answer
f(g(x)) plugs g(x) into f, so f(g(x)) = m1*(m2*x+b2)+b1.
f(g(x)) = m1(m2x+b2)+b1
How to use the Composite Function Calculator
- 1Enter the slope and intercept for f and for g.
- 2Enter the x value to evaluate.
- 3Read both compositions f(g(x)) and g(f(x)) — they are usually different.
Worked example
Using the values the calculator loads with:
Inputs
- f slope m12
- f intercept b11
- g slope m23
- g intercept b2-2
- x value4
Results
- f(g(x))21
- g(x)10
- g(f(x))25
- f(x)9
Frequently asked questions
Is f(g(x)) the same as g(f(x))?
Not usually — function composition is not commutative in general.
Can this handle non-linear functions?
This tool models linear functions; substitute manually for higher-degree functions.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.