Simplify:

y^{a – b} × y^{b – c} × y^{c - a}

y^{a – b} × y^{b – c} × y^{c – a} = y^{(a-b + b-c + c-a)}

(Product Rule: a^m × aⁿ = a^{m + n} , where ‘a’ is a real no. and m, n are positive integers.)

⇒ y^{a – b} × y^{b – c} × y^{c – a} = y^{(a-a + b-b-c + c)}

⇒ y^{a – b} × y^{b – c} × y^{c – a} = y⁰

⇒ y^{a – b} × y^{b – c} × y^{c – a} = 1

(∵ Number with zero exponent rule: If ‘a’ is a rational no. other than zero, then a⁰ = 1)