Question 82734
N=F+d(n-1)


Perhaps you mean to solve for lower case n!  It is very important to realize that in math, when upper case and lower case letters are used in an equation, they represent DIFFERENT variables.  If you really wanted to solve for capital N, then the given equation does that already.  However, assuming that you want to solve for "n", first remove the parentheses by distributive property:
N= F+ dn - d


Next, get all the NON-"n" terms on the left side, and get the "n" term (that is, "dn") by itself.  You can do this by subtracting F and adding d to each side:


N= F+ dn - d
N-F +d = F+dn-d -F +d
N-F + d = dn


Next, divide both sides by d, so as to "undo" the multiplication of d times n:
{{{(N-F + d)/d = (dn)/d}}}

{{{(N-F + d)/d = n}}}


Resist the temptation to reduce this expression by dividing out the d's!  You NEVER DIVIDE OUT TERMS!!!


R^2 at SCC