x = 12 (option C)
JK = 17 (option C)
Step-by-step explanation:
Parts A:
line KJ = x + 5
line MJ = 2x - 7
The base angles are equal = 90 degrees. Hence the base will be equal.
line KJ = line MJ
x + 5 = 2x - 7
collect like terms:
x - 2x = -7 - 5
-x = -12
Divide both sides by -1:
-x/-1 = -12/-1
x = 12 (option C)
Part B:
line KJ = x + 5
JK = 12 + 5
JK = 17 (option C)