Can someone explain this? ?

b) determine the first value of the arithmetic sequence in
which t70 = 500 and d = -43.

Find the measure of the interior angles of the following regular polygons: a triangle, a quadrilateral, a pentagon, an octagon, a decagon, a 30-gon, a 50-gon, and a 100-gon.

If 2(a^2+b^2)=(a+b)^2 then, > a+b=0, > ab=0, > a=b, > 2a=b

You have 138.72 in your saving account u take out 45.23 and 18.00 you deposit 75.85 into your account