How can u determine the total cost of an item including tax if you know the price of the item and the tax rate

There are 2 ways. You can take the initial price and multiply it by the tax rate and then add them together, or you can take the tax rate and add 1 to it and the product will be the final answer.

For example:
If the price is 2 and the tax rate is 7 cents a dollar, it will look like this:
2.00 * .07 = .14
2.00 + .14 = 2.14
OR
2.00 * (1 + .07) 
2.00 * 1.07 = 2.14

X^2 - 4x +(4/2^2) + y^2 + 8y + (8/2^2) = -4 + (4/2^2) + (8/2^2)(x + 2)^2 + (y + 4)^2 = -4 + 4 + 16your center is (-2, -4) and the radius is the sqrt of -4 + 4 + 16 which is 4