Find g(f(x)) where g(x)=2x+4 and f(x)=x^2+1.

With functions of functions you work from the inside out, so you substitute the function f(x) for the x in g(x). We know that f(x)=x2+1 and g(x)=2x+4. In this question you therefore replace the x in 2x+4 with x2+1. This leads to g(f(x))=2(f(x))+4, or g(f(x))=2(x2+1)+4. The next step is to expand the brackets, giving 2x2+2+4, and then to collect like terms to give g(f(x))=2x2+6.

Answered by Georgina M. Maths tutor

2135 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

How do you simplify a surd?


Find the points at which the equation y = x^2 - 12x + 35 intersects the x-axis.


A rectangle has an area of 20 cm2. Its lengths are enlarged by a factor of 3. What is the area of the new rectangle?


Can two shelves of 0.72 meters long each store 50 30mm wide textbooks?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences