Mark H. answered 09/11/19
Tutoring in Math and Science at all levels
You have 2 unknowns, so you need 2 equations. Let's use X and Y for the 2 unknown sides:
Because you have a right triangle, and you know the hypotenuse, you can use the Pythagorean Theorem:
x2 + y2 = 852
You are told the difference between the 2 sides:
x = y + 71
Now you have 2 equations. Use the expression for x in the 2nd equation, and substitute into the first:
(y + 71)2 + y2 = 852
Expand this, simplify, and put in standard form. Then you will be able to solve it using the standard methods for quadratics.