Which expression would demonstrate the use of the commutative property in addition in the first step of simplifying the expression (-1+i)+(21+5i)

Create a real-life situation and create a system and show how it might be modeled algebraically with a system of equations (or inequalities) show all work include a few sentences explaining the situation, your variables of choice and what each represents, and how you would set it up and solve it algebraically. !

Weak battery is considered to be a part of routine a. inspection b. wear and tear c. maintenance d. check

The coordinates r(1, -3), s(3, -1) t(5, -7) form what type of polygon? a right triangle an acute triangle an equilateral triangle an obtuse triangle