solve 4-(X+1)=8

Question

How to solve b distributing a negative

Answer 1

When distributing a negative sign, you are basically distributing a -1. To see this more clearly, you can change the negative sign to a positive and put a -1 right after it so you know to multiply everything inside the parentheses by -1. Once you've distributed the -1, all you have to do is add like terms and solve for x.

     4 - (x + 1) = 8     ==>     4 + -1(x + 1) = 8

                                           4 + (-1(x) + -1(1)) = 8

                                           4 + ((-x) + (-1)) = 8

                                           4 + (-x - 1) = 8

                                           4 - x - 1 = 8

                                           3 - x = 8

Now, solve for x:    

                             3 - x = 8

                          - 3         - 3

                       ______________

                             3 - 3 - x = 8 - 3

                                  0 - x = 5    

                                     - x = 5

                                    -1x = 5

                             -1x / -1 = 5 / -1

                                      x = -5

Answer 2

Hello Earle,

In this problem there's an invisible 1 outside the bracket. Actually it looks like this

4 -1(x + 1) = 8

So. now you distrbute the minus and 1 together and open the brackets

4 + (-1)(x) + (-1)(1) = 8

4 - x - 1 = 8

3 - x = 8

subtract 3 from both sides

3 - 3 - x = 8 - 3

-x = 5

multiply both sides by -1

(-1)(-x) = (5)(-1)

x = -5 ------> answer