You can think in reverse. Addition is the opposite of subtraction. So to solve 15-8, you can ask "8 plus what number is equal to 15?" and note how 8+7 = 15. So that's why 15-8 = 7. Similarly, 15-7 = 8 can be solved the same way.
The answer is the last option
Which is (49x-16)^2
To find the greatest common factor of 40 and 27, we can first start by making a list of factors for each number.
The factors of 27 are: 1, 3, 9, 27
The factors of 40 are: 1, 2, 4, 5, 8, 10, 20, 40
When looking at these numbers, we can see that 1 is the greatest common factor of both 40 and 27.
Flower bed A:
circumference= 2 x pi x r= 2x pi x10/2
=10pi feet
Area= pi x r^2=25pi square feet
Flower bed B:
circumference=12 pi feet
Area=36 pi square feet
