how do you determine the fraction of parent isotope remaining after 20,000 years if the isotope used has a half life of 5000 years

What is [tex] {7}^{98 + \sqrt{4} } - 3 \times (64 \div 2 + 4 - 36) \times a = a + 36[/tex]?

Can somebody 1. what is the formula for finding the vertical distance between two points on a coordinate plane?

Erinn wrote the equation –5x + 4y = 32 to represent her hourly wage (y) and how this wage has changed during each year that she worked at a company (x). what is the rate of change in erinn's hourly wage per year?