Question

if a/b=b/c , p.t. (a+b+c)(a-b+c)=a^2+b^2+c^2​

Answer 1

Step-by-step explanation:

given,

a/b= b/c

b²= ac

to prove: (a+b+c)(a-b+c)=a²+b²+c²

proof:(a+b+c)(a-b+c)=a²+b²+c²

LHS: (a+b+c)(a-b+c)

(a²-ab+ac+ab-b²+bc+ac-bc+c²)

(a²-b²+c²-ab+ab-bc+bc+ac+ac)

(a²-b²+c²+2ac)

(a²-b²+c²+2b²) [b²=ac]

(a²+b²+c²)

hence LHS=RHS

.......666.......