I am not quite sure where to go in determining the number of details

Which expression gives the area of the triangle shown below

Solve with work both bert and ernie received an increase in their weekly salaries. bert's salary increased from $520 to $520. ernie's salary went from $580 to $645. find the percent of increase for each salary. what was the larger of the two percents ?

Find the greatest common factor of the followig monomials 21u^5v,3u^4v^6, and 3u^2v^5