A sample of a radioactive isotope had an initial mass of 600 mg in the year 2003 and decays exponentially over time. A measurement in the year 2007 found that the sample's mass had decayed to 350 mg. What would be the expected mass of the sample in the year 2011, to the nearest whole number?

%40

step-by-step explanation:

5=812a+9+3

step 1: simplify both sides of the equation.

5=812a+9+3

5=(812a)+(9+3)(combine like terms)

5=812a+12

5=812a+12

step 2: flip the equation.

812a+12=5

step 3: subtract 12 from both sides.

812a+12−12=5−12

812a=−7

step 4: divide both sides by 812.

812a /812 = -7/812

a= -1/116

so the answer is

a=   -1/116

step by step explanation: when u removing the parentheses and combined them that would be : x+3y-x-y=2y