What is the solution set of the quadratic inequality (x^2)-5≤0

On a piece of paper graph f(x)=5•(0.4)^x

Select a graph that have an equation with a < 0

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