The amount of passwords possible is:

Since he only tries once for the first try we get:

Thus there is a:

Chance he will guess the password on his first try.

**Answer:**

If m is the midpoint of ab it means am is equal to mb

am = 3x + 8 and mb = 6x-4

and ab = am + mb

first find the value of x by using am = mb

3x + 8 = 6x - 4

8 + 4 = 6x - 3x

12 = 3x

x = 4

ab = 3 (4) + 8

= 12 + 8 = 20 = mb

ab = am + mb

= 20 + 20

40

so, the value of ab is 40

Lets see!

We need to use the pythagorean theorem (a^2+b^2=c^2) to check.

So..

15^2+ 17^2 = 19^2

225+ 289= 361

Hm 225 and 289 do NOT equal 361 therefore it is NOT a right triangle.