Suppose that f(A,B,C) means A-2C + (1/2)AB
A. Find f(2,3,-11)
B. Find f(D,5,D)
C. Find f(3,4,f(-5,7,4))
just do what it says...
f(A,B,C) = A-2C + (1/2)AB
f(2,3,-11) = 2 -2(-11) + (1/2)(2)(3)
= 2 + 22 + 3 = 27
f(D,5,D) = D - 2D + (1/2)(D)(5)
= D - 2D + (5/2)D = (3/2)D or 3D/2
for the last one,
f(-5,7,4) = ?
then f(3,4,? ) = ....
you try it.