Question 729274
You look for amount of gold divided by amount of alloy.


Initially, amount of alloy is {{{6*8=48}}} grams.  Amount of gold in the initial alloy is {{{0.90*48=43.2}}} grams.  


Begin to construct the G(x) function.
Addition of x grams of silver changes the fraction of gold.  This fraction may be represented as a decimal.
{{{(43.2)/(48+x)=G}}}, where G is the fraction of alloy which is gold.  We remind ourselves that G is a function of x.
{{{highlight(G(x)=(43.2)/(48+x))}}}.