Given f(x)= 8 − x^2, solve f(3x) = -28

First substitute (3x) into the equation for f(x), giving f(3x) = 8 - 9x2. This is then equal to -28 and so it is remains to solve the equation 8 - 9x2 = -28. This can be written as 9x2 = 36, dividing through by 9 gives x2 = 4 and so x = ±2.

GG
Answered by George G. Further Mathematics tutor

3316 Views

See similar Further Mathematics GCSE tutors

Related Further Mathematics GCSE answers

All answers ▸

A curve is defined by the equation y = (x + 3)(x – 4). Find the coordinates of the turning point of the curve.


A curve has equation y = x^2 - 7x. P is a point on the curve, and the tangent to the curve at P has gradient 1. Work out the coordinates of P.


How can I show that the lines between sets of points are perpendicular?


Why does tanx = sinx/cosx ?


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