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.

GM
Answered by Georgina M. Maths tutor

2295 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

How do I simplify a surd?


Shampoo is sold in two sizes. 1) 500 ml for £1.98 2) 3 litres for £12.80 (now 15% off). Which is better value for money?


Find the x-Coordinate of the minimum point of the function: f(x) = x^2 + 2x - 5


Given 4x+7y=25 and 2x+5y=17, identify x and y by solving the simultaneous equations


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences