Answer:
1
Step-by-step explanation:
Look at the LHS: you have the square of x, then you have 2 times x, times -1. to complete a square you just need to add the square of -1, that is 1. That becomes

First of all not to be rude, but it is order of operations not properties of operations. Second, you can solve equations by going in the order of PEMDAS or Parentheses, Exponents, Multiplication, division, addition, and subtraction. Multiplication and division are switchable, addition and subtraction. If you do not follow this order you get the equation or inequality wrong.
Answer:
3
Step-by-step explanation:
18 -15 = 3