Question

1. Is -7 + 9= -9 + 7 true, false, or open

Answer 1

1. -7 + 9= -9 + 7 is false 
2. Is 4x - 3 = 19 is open, because this could be a valid equation.
 3. 16 = 4x - 4 
  So, 16+4=4x; 4x=20; x=20/4; x=5..... option C is the correct one.
 4. length of the classroom is 2.4 times its width. 
  given length = 42 in, and since length = 2.4 times width, width = 42/2.4,
hence option A) 17.5 in is correct
 5. x - 3 = 10
  x = 10+3 =13
 Option B is the right one.