''Why do you think we measured length and width in “feet,” but we measure area in “square feet?”

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

What is the absolute value of the complex number -4-sqrt2i

Diane’s bank is offering 5% interest, compounded monthly. if diane invests $10,500 and wants $20,000 when she withdrawals, how long should she keep her money in for? round to the nearest tenth of a year.