Count to find the slope​

Which values for a and b will create infinitely many solutions for this system of equations? ax-y=8 2x+y=b

The class wants to raise a total of $750.if they receive a profit of $1.25 from each candybar sold, how many bars must they sell to reachtheir goal

Consider the function y = f(x)=3^x the values of f(1/2) and f(1/4). rounded to the nearest hundredth, are__and__ respectively