Solve using addition method. 3x - 7y = 16 5x -7y = 36

What is the number 321,000,000 in scientific notation? also what is the number? ?

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed

1yd 1 ft = 1 1/12 1 1/3 1 1/2 1 1/6