In rhode island, sales tax is 7.0%. what is the tax on items that total $140.88 before tax?

If you are asking for what the tax is then you take x over 140.88 and 7 over 100 and you cross multiply to get 100x and 986.16 then you divide 100x and 986.16 both by 100 so you get x = 9.8616 but sense .0016 are not cents you round that and get $9.86 as your Tax price and the total amount you would end up paying would be 9.86 + 140.88 which is 150.74 so you would end up paying $150.74 all together but the Tax of 7% is 9.86 for this problem Hope this helped

9.86 is the sales tax 

The graph is shown below.

Explanation:

The midline here is y = 0, which is right on top of the horizontal x axis. One point on the curve that's on the midline is the origin (0,0). This is marked as point A in the diagram below.

Point B is one of the infinitely many minimum points, aka lowest point. We determine this by noticing that sin(x) maxes out when x = pi/2 = 1.57 approximately. You should find that this x value leads to y = -2. So the location of point B is approximately (1.57, -2).

I used GeoGebra to make the graph. Desmos is another option you can use. Both are free.