Can someone help me out

Describe the possible echelon forms of the standard matrix for a linear transformation t where t: set of real numbers is onto.

Find the number of real number solutions for the equation. x2 + 5x + 7 = 0 0 cannot be determined 1 2

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