Sales tax is 0.07 so the combined price of the cell phone and the tax would be 1.07 of $79.99. So multiply 1.07 by 79.99:
79.99 * 1.07 ≈ 85.59
The cell phone will cost $85.59.
It is approximate because the actual value of 1.07 * 79.99 is 85.5893 but I rounded up.
