solve 5z + 11 = 1

Question

 please solve the above question, and the answer from the book is z ≤ -2. 

Answer 1

Gregorio,

 

As Sherry showed you in her solution, the answer to the problem as stated is exactly z = -2.  If the book says it is z ≤ -2, then the book is giving you the answer to 

 

5z + 11 ≤ 1,

 

which is a slightly different problem.  Was the problem supposed to be

 

5z + 11 ≤ 1 ?

Answer 2

If the book says ≤ then the question should probably have the same equality symbol [instead of =]. However, I will solve it as you have presented it.

 

5z + 11 = 1

       -11  -11

5z = -10

÷5     ÷5

 

z = -2

 

Have a good evening!