Explain proportion

Question

Explain why a and a+b can never form a proportion.

                  b          b

Answer 1

let's assume it can

 

then b(a+b) must equal ab  (product of means = product of extremes)

 

ab + b^2 = ab

 

subtract ab from both sides

 

b^2 = 0

 

b = 0

 

can't divide by zero!!