Answer:
First off, I can't solve for y, there is no y variable.
Second, 3 = 7 ( 1 - 1 ) is not true because 3 ≠ 0 ( 3 doesn't equal 0 ) :
3 = 7 ( 1 - 1 )
3 = 7 ( 0 ) ( Simplify Parenthesis )
3 = 0 ( Multiply 7 and 0 )
3 ≠ 0