a billboard has the given dimensions 7^2 ft(width) and 4^2 ft (height) using exponents write two equivalent expressions for the area of the rectangle.

bdhfnfhjffjkfjfjfjjf

ending amount = beginning amount / (2^n)

where "n" = number of half-lives (or elapsed time / half-life)

ending amount = 50 mg / (2 ^10 / 5.3)

ending amount = 50 mg / (2 ^ 1.8867924528)

ending amount = 50 m / 3.6981210597

ending amount = 13.5203794557 mg

or about 13.5 mg remain

source:  

y-y1=m(x-x1)

y-1=1(x-8)