Answer
a) height = $2x-1$
b) area = $\frac{1}{2}x(2x-1)$
c) 248 cm$^2$
Work Step by Step
a) To write an expression for one less than twice the length, you multiply the length by 2 and subtract 1 from the product.
b) The area of a triangle is $\frac{1}{2}$ the length times the height.
c) $\frac{1}{2}x(2x-1)\longrightarrow$ substitute 16 for x and solve
$\ \ \ $=$\frac{1}{2}(16)(2\times16-1)$
$\ \ \ $=$8(31)$
$\ \ \ $=$248$
