First error is that the legs are a and b so a should be x and b is 6 and c is 10 the second error is at the end they did not take the square root to get x by itself the real answer should be
X^2 +6^2=10^2
X^2+36=100
X^2 =64
X=8
Where what assignment are you talking about
Answer its 82 i added the cm
-10 and -2
Because -10-2= -12 and -10 x -2 = 20
Hope this helps :)