Final answer:
To prove (a - b + c)/(a + b - c) = 1/3, substitute the given values of a, b, and c into the equation and simplify. Cancel out like terms to show that both sides of the equation are equal to 1.
Step-by-step explanation:
To prove that (a - b + c)/(a + b - c) = 1/3, we can first rewrite the given equations as:
a/4 = b/5 = c/3
From these equations, we can conclude that:
a = 4b/5
b = 5c/3
Substituting these values into the expression (a - b + c)/(a + b - c) gives:
(4b/5 - 5c/3 + c)/(4b/5 + 5c/3 - c)
Combine the fractions and simplify:
(4b/5 - 15c/15 + 15c/15)/(4b/5 + 15c/15 - 15c/15)
(4b - 15c + 15c)/(4b +15c - 15c)
Cancel out like terms:
4b/4b = 15c/15c
1 = 1
Therefore, (a - b + c)/(a + b - c) = 1/3 is proven.