Answer
15
Work Step by Step
Sketch:
Linear function: $f(x)=8-2\mathrm{x},$ bounds: x=0 to x=3.
(see below)
We see a trapezoid,
with (vertical) bases 8 and 2,
and the height (from base to base) of 2.
$A=(\displaystyle \frac{b_{1}+b_{2}}{2})h=(\frac{8+2}{2})\cdot 3=5\cdot 3==15$
$A=\displaystyle \int_{0}^{3}(8-2x)dx=15$
