A Roofing Contractor Is Fabricating Gutters From $10$ -Inch Aluminum Sheeting $a = 10 - 2 x$

Multiple Choice

A roofing contractor is fabricating gutters from $10$ -inch aluminum sheeting.The contractor plans to use an aluminum siding folding press to create the gutter by creasing equal lengths for the sidewalls (see figure) . ​ where $a = 10 - 2 x$ Let x represent the height of the sidewall of the gutter.Write a function A that represents the
Cross-sectional area of the gutter.
​

A) $A = - 2 x ^ { 2 } + 10 x$
B) $A = 10 x ^ { 2 } - 2 x$
C) $A = - 10 x - 2 x ^ { 2 }$
D) $A = 2 x ^ { 2 } - 10 x$
E) $A = 2 x ^ { 2 } + 10 x$