SOLUTION: prove that -1(a)=-a

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: prove that -1(a)=-a      Log On


   

Question 1171491: prove that -1(a)=-a
Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!


Look at -a first.



Add a:  -a + a = 0   (by the definition of the additive inverse)





Look at -1(a) next.

Add a:  -1(a) + a

Factor:  = a(-1 + 1)

Simplify: = a(0) = 0



This has shown  -1(a) + a = -a + a,  thus  -1(a) = -a and the proof is

complete.