Anyone know this? i don’t know the answer to this

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

Using elimination, what is -4x+2y=-12 4x+8y=-24

What is 100,000 times 1/100,000, using the standard method of multiplication? write the answer as 10 to a power.