Question

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The radioactive substance strontium-90 has a half-life of 28 years. In other words, it takes 28 years for half of a given quantity of strontium-90 to decay to a non-radioactive substance. The amount of radioactive strontium-90 still present after t years is modeled by the expression grams. Evaluate the expression for t = 0, t = 28 and t = 56. What does each value of the expression represent?

Answer 1

expression is 80*2^-t/28

Answer 2

@eliassaab @michelleg46 @lgbasallote @shadowfiend and others help

Answer 3

@shadowfiend @anonymoustwo44 @lgbasallote @rebeccaskell94 @razor99 help

Answer 4

@dumbcow @dpaInc

Answer 5

As you know \(2^{1} =2 \) and \(2^{2} = 2\cdot 2\)
More tricky is \( 2^{-1}= \frac{1}{2^1} =\frac{1}{2} \) and \(2^{-2} = \frac{1}{2\cdot 2}\)
(A negative exponent means "flip upside down" and make the exponent positive.

A very important fact is \(2^0=1 \) Any number (except 0) to the zero power equals 1