Answer:
[tex]A=3w^2-8w[/tex]
When w=10 then A=220 square cm
Step-by-step explanation:
To calculate an area of a rectangle, use the formula A=l*w. We know the length is 8cm less than 3 times the width. So l = 3w - 8.
So the area is [tex]A= (3w - 8)*w = 3w^2-8w[/tex]
If the width is 10 then substitute w=10 into the polynmial.
[tex]A= 3w^2-8w\\A=3(10)^2-8(10)\\A=300-80\\A=220[/tex]