The average atomic mass of a sample of an element x is 16.2 u what are the percentage of isotopes

Elena and her husband marc both drive to work. elena's car has a current mileage (total distance driven) of 15,000 and she drives 23,000 miles more each year. marc's car has a current mileage of 46,000 and he drives 9,000 miles more each year. will the mileages for the two cars ever be equal? explain.

What is the expression in factored form? -20x^2 - 12x a. 4x(5x+3) b. -4x(5x-3) c. -4(5x+3) d. -4x(5x+3)

How many heads would you expect if you flipped a coin twice? first, fill in the table below with the correct probabilities. hint: the sample space for flipping a coin twice is {hh, ht, th, tt}. a = b = c = f