Formula for are of a rectangle:
A =L * W
1st isolate W
147 = 3W * W
147 = 3W^2
divide 147 by the by 3 on bot sides
29 = W^2
get ride of the square by square rooting on both sides
7 = W
2nd find the perimeter
P = 2(7) + 2(21)
P = 14 + 42
P = 56
The difference between your speed is 6 miles per hour: that means that every hour you move 6 miles relative to your friend. But you only need to catch up 3 miles: half of it. So you'll catch up after 30 minutes.
First, you need to see which number all of these numbers have in common, and that is number 4. So, let's start:
-4(x2 - 4x + 6)
The expression in the brackets cannot be factored further, which means that the answer above is the complete factor of the original expression. Hope it helps. :)
