Landon used a semicircle, a rectangle, and a right triangle, to form a figure below. which is the best estimate of he area of the figure in square centimeters?
5x-15 = -65
add 15 to each side
5x = -50
divide by 5 on each side
5x/5 = -50/5
x = -10
7 x 400= 2,800
7 x 550= 3,850
the series is an arithmetic series with first term (a1) -9 and common difference (d) 5. then the general term (an) is
an = a1 +d(n-1) = -9 +5(n-1) = -14 +5n
the summation notation indicates the sum of "n" of these terms.