The perimeter of a rectangle is 30 inches. If its length is three times its width, find the dimensions. 30 inches=2(L+W) Divide each side by 2. 15 inches=L+W Substitute for L.
Answer :

Step-by-step explanation :
To find the product of

First we expand the bracket ,
it implies that, we use the expression outside the bracket to multiply individual expressions inside the bracket.
Hence


we now apply the law of indices

meaning, when you are multiplying two expressions with the same bases , repeat one of the bases and add the exponents.
Then, simplify to obtain
21 divide by 4 is 5.25. She travels 5.25 miles per hour. 42 divide by 5.25 is 8. It would take 8 hours for Shelly to bike 42 miles.