I need help, I don't know how to do it.

Step-by-step explanation:

to solve this problem we can use the Pythagorean theorem

UT and TL are the legs, while LU is the hypotenuse

We have to find LU so we can proceed like this

x^2 + (x+1)^2 = LU^2

x^2 + x^2 + 1 + 2x = LU^2

2x^2 + 2x + 1 = LU^2

LU = +/-

we have to take only the positive value because a length can’t be negative.

2x^2 + 2x + 1 is positive for every value of x, so the final answer is