Question 1104402
<font color="black" face="times" size="3">
First find the expression for f(a+h)
f(x) = x^2 - 3
f(x) = (x)^2 - 3
f(a+h) = (a+h)^2 - 3 ... replace every x with a+h
<font color=blue>f(a+h) = a^2+2ah+h^2 - 3</font> ... expand out (a+h)^2. 
I'm marking it in blue so we can use it later
----------------------------------
Then do the same for f(a)
f(x) = x^2 - 3
<font color=red>f(a) = a^2 - 3</font> ... replace every x with 'a'
I'm marking it in red so we can use it later
----------------------------------
Now that we know f(a+h) and f(a), we simply subtract
<font color=blue>f(a+h)</font> - <font color=red>f(a)</font> = [ <font color=blue>f(a+h)</font> ] - [ <font color=red>f(a)</font> ]
<font color=blue>f(a+h)</font> - <font color=red>f(a)</font> = [ <font color=blue>a^2+2ah+h^2 - 3</font> ] - [ <font color=red>a^2-3</font> ]
f(a+h) - f(a) = a^2+2ah+h^2 - 3 - a^2 + 3
f(a+h) - f(a) = 2ah+h^2
----------------------------------
----------------------------------
Final Answer: 2ah+h^2
</font>