Step-by-step explanation:
a. x - x + 5 = -4
  5 ≠-4
b. 2x - 2x + 5 = 5
  5 = 5
infinitely many solutions
+25 = x
step-by-step explanation:
here x is the hypotenuse of a right triangle whose legs are 7 and 24. by the pythagorean theorem, 7² + 24² must equal x²:
x² = 49 + 576 = 625. thus, x = +√625 = +25 = x