Why is the answer to 12x12 the same as 6x24?

Use the function f(x) is graphed below. the graph of the function to find, f(6). -2 -1 1 2

Tomas is making trail mix using granola and walnuts. he can spend a total of $12 on the ingredients. he buys 3 pounds of granola that costs $2.00 per pound. the walnuts cost $6 per pound. he uses the equation to represent the total cost, where x represents the number of pounds of granola and y represents the number of pounds of walnuts. he solves the equation for y, the number of pounds of walnuts he can buy. answer- b tomas added 6 to both sides of the equation instead of subtracting 6. just took the test

Given f(x)= 9x+1 and g(x)=x^3, choose the expression (f*g)(x)