Calculate the sum of the areas of two rectangles below: a) mn+ 9m - 10
b) n + 3 + 3m - 5
c) mn + 9m + 5
d) 12

9m+mn-10

Steps: we know that the area of a rectangle or square is base times height
So multiply 2 with 3m, which would be 6m
Then multiply 2 with -5, which would equal -10. So u found the area of rectangle one which is 6m-10

To find the area of rectangle 2 do the same steps listed above.
You end up getting 3m+mn

Then lastly the question is asking to find the sum of both areas so add up (6m-10)+(3m+mn)
Add like terms and you should get
9m+mn-10