Explanation
The area under a curve between two points can be found by doing a definite integral between the two points
Step 1
a) set the intergral
[tex]\begin{gathered} limits:\text{ 1 and 2} \\ function:\text{ f\lparen x\rparen=6-2x} \end{gathered}[/tex]hence
[tex]Area=\int_1^26-2x[/tex]Step 2
evaluate
let ; numbers of intervals
[tex]\begin{gathered} \begin{equation*} \int_1^26-2x \end{equation*} \\ \int_1^26-2x=\lbrack6x-x^2\rbrack=(12-4)-(6-1)=8-5=3 \end{gathered}[/tex]therefore, the area is
[tex]area=3\text{ units }^2[/tex]
I hope this helps you