Question

Suppose that a doesn't equal 0.
a) If a.b = a.c, does it follow that b = c?
b) If axb = axc does it follow that b = c?
c) If a.b = a.c and axb = axc, does it follow that b = c?

Answer 1

look at this website:
www.math.ucla.edu/~ronmiech/Calculus_Problems/32A/chap11/section4/709d39/709_39.html

Answer 2

I don't under even after looking at the site.