Step-by-step explanation: The fractions have unlike denominators. First, find the Least Common Denominator and rewrite the fractions with the common denominator.
LCD(3/5, 21/25) = 25
Multiply both the numerator and denominator of each fraction by the number that makes its denominator equal the LCD. This is basically multiplying each fraction by 1. Finish the multiplication The two fractions now have like denominators so you can subtract the numerators.The two fractions now have like denominators so you can subtract the numerators. Then boom you have -6/25 good luckkkkkkk
The answer is 36. I know this because since one of the lengths of the room is 8, you take 80 and divide it by 8 which gives you 10. So now that you know the two side lengths you add. 10+10+8+8 which is 36.
