Cambridge O Levels Add Maths HELP!!

[TheGhostOfHonor]

hi guys, I will be appearing in o levels in oct/nov 2016, all I need from you Is to post your questions and also solve mine, currently I'm having problems in May/June 2014 p22 Q)11 (i). I do not understand how f(x) > 3, where it clearly looks like f(x) > -1 since 2^x > 0, 2^x -1 > -1 , thus f(x) > -1. NOTE: all answers are checked from marking scheme.

 

[MorganMilessi45]

The questions states that "The functions f and g are defined, for real values of x greater than 2". So when x=2 is substituted in the equation, f(2)=2^2 - 1 = 3. Hence f(x) > 3

 

[TheGhostOfHonor]

Thanks for the help......