9 is only true for this particular problem. If you replace let's say "2" with "x" in the parenthesis and solve for "x" having "9" on the right hand side. You never get x = 2; it will be 1.6666..
So I never teach my students this way as it is not consistent. Correct way is, if there appear a parenthesis in the expression it has priority over division and need to be solved first. This way correct answer is 1.
Which also stands if you replace "2" by x and solve for "1" on the right hand side.
9 is only true for this particular problem. If you replace let's say "2" with "x" in the parenthesis and solve for "x" having "9" on the right hand side. You never get x = 2; it will be 1.6666..
So I never teach my students this way as it is not consistent. Correct way is, if there appear a parenthesis in the expression it has priority over division and need to be solved first. This way correct answer is 1.
Which also stands if you replace "2" by x and solve for "1" on the right hand side.
makes sense