What is ab? i don't get this problem. !

AB = x

6^2 = x * (x+5)

36 = x^2 +5x

x^2 +5x - 36 = 0

(x-4) (x+9) = 0

x = 4, x = -9

 it can't be a negative so x = 4

 AB = 4 cm

The problem consists in finding the new length of a running trail knowing the original length and the extension required. So the new length will be equal to original length + extension. New length = 2.826 miles + 1.46 miles = 2.826 miles + 1. 460 miles (I added a 0 in the place of the thousandths for the second summand to make clear the sumation) = 4.286 miles. Then the answer is 4.286 miles.