When solving for the value of x in the equation 4(x - 1) + 3 = 18,
Aaron wrote the following lines on the board.
[line 1] 4(x - 1) + 3 = 18
[line 2] 4(x - 1) = 15
[line 3] 4x - 1 = 15
[line 4] 4x = 16
[line 5] x=4
Which property was used incorrectly when going from line 2 to line 3?
(1) distributive (3) associative
(2) commutative (4) multiplicative inverse



Answer :

(1) distributive is the answer. Distributive property just means 4(x-1)=4x-4
    4(x - 1) + 3 = 18
4(x) - 4(1) + 3 = 18
      4x - 4 + 3 = 18
            4x - 1 = 18
                + 1   + 1
                 4x = 19
                  4      4
                   x = 4³/₄
The answer is line 3.