What number can be used as a common denominator for the fractions 1/4 and 5/6

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

What is the solution set of the quadratic inequality x^2-5< or equal to 0

Y=(x+3)(x-4)(x+1)^2 sulutions? multiplicity?