Question

The length and width of a rectangle are shown below.

A rectangle with a length of 2-x plus 10 and a width of 50 minus x.

Which expression represents the area, in square units, of the rectangle?

A.
2
x
2
−
90
x
−
500

B.
−
2
x
2
−
90
x
−
500

C.
−
2
x
2
+
90
x
+
500

Answer 1

Interpret the length as 2x + 10 and the width as 50 − x.
Area = (2x + 10)(50 − x) = 2x·50 − 2x·x + 10·50 − 10·x = 100x − 2x^2 + 500 − 10x = −2x^2 + 90x + 500.

So choice C.