If f(x)=7-4x, given that f(c)=9, find c

  • Google+ icon
  • LinkedIn icon
  • 714 views

f(c) means let x=c. Remember that c is just an unknown number.

The expression f(c)=9 means that when we put c through the function f(x)=7-4x, it gives the answer 9. Therefore we know 7-4c=9 is true.

Now we have an equation that we can go through in the normal way:

7-4c=9

-4c=2

4c=-2

c=-0.5

Emma F. GCSE Maths tutor, Mentoring -Medical School Preparation- tuto...

About the author

is an online GCSE Maths tutor with MyTutor studying at St. Andrews University

Still stuck? Get one-to-one help from a personally interviewed subject specialist.

95% of our customers rate us

Browse tutors

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok