For the first point, remember this simple rule: every exponential function [tex] a^x [/tex] always returns [tex] a [/tex] when evaluated at [tex] x = 1 [/tex]. In fact, [tex] a^1=a [/tex] for every possible base [tex] a [/tex].
So, we can see that the graph of the exponential passes through the point [tex] (1,y) [/tex] where [tex] y [/tex] appears to be between 1 and 2. So, the only feasible option would be [tex] y = 1.8^x [/tex], because it passes throught the point [tex] (1,1.8) [/tex] because [tex] f(1) = 1.8^1 = 1.8 [/tex].
The other functions are wrong because:
As for the second question, you simply have to plug in the values: the function
[tex] f(x) = 7^x [/tex]
means that you have to choose an input, x, and use it as exponent for 7. So, if you choose x=2, it means that you have to give exponent 2 to 7, i.e. you replace the x with the specific value, 2.
So, the expression becomes
[tex] f(2) = 7^2 = 49 [/tex]
