Pascal's triangle is a way of organizing the coefficients in the binomial expansion, [tex](a+b)^n[/tex]:
n = 0 => 1
n = 1 => 1 1
n = 2 => 1 2 1
n = 3 => 1 3 3 1
n = 4 => 1 4 6 4 1
and so on, where each row starts and ends with a 1, and the numbers in the middle are obtained by adding together the two numbers directly above and to the left. These coefficients are then mulitplied by descending powers of a and descending powers of b (or vice versa, because the pattern is symmetric), starting with 0 and going up to n.
In this case, we have
[tex](x+4)^3=1\cdot x^3\cdot4^0+3\cdot x^2\cdot4^1+3\cdot x^1\cdot4^2+1\cdot x^0\cdot4^3[/tex]
Notice how the powers of x and 4 always sum to n = 3.
Simplifying, we get
[tex](x+4)^3=x^3+12x^2+48x+64[/tex]
so that
a = 1
b = 3
c = 12
d = 2
e = 48
f = 1
g = 64
