If n is an integer, f(n) = f(n-1) - n and f(4)=12. What is the value of f(6)?  Choose one:
A) 1
B) 0
C) -1
D) 2
E) 4
Since f(n)=f(n-1)-n then: f(6)=f(5)-6 and f(5)=f(4)-5.   As given that f(4)=12 then f(5)=12-5= 
<gadget id="calculator">12-5</gadget>
<output>7</output>
7 --&gt; substitute the value of f(5) back into the first equation: f(6)=f(5)-6=7-6= 
<gadget id="calculator">7-6</gadget>
<output>1</output>
1.   Answer: A.   Questions on funtions to practice:
<result>A</result>
If n is an integer, f(n) = f(n-1) - n and f(4)=12. What is the value of f(6)?