Hello! :)
Let's use PEMDAS.
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction
(5-2) = 3 Do parenthesis.
7 × 3 = 21 Multiply with what we got after doing the parenthesis.
9 + 21 = 30 Add with what we had left.
30
Hope this helps!
ELITEDIPER
The maximum amount of space can be acquired by having 15 ft of fence of 2 long sides of the rectangle while the short sides should be 5 ft each
So we are trying to find what multiplied by 10 is 4000. To figure that out, you can just divide 4000 by 10 to get 400. 400 x 10 = 4000.
You can also see from the second line that it says (50 x 8) x 10. So the unknown number is 50 x 8, which is also 400.