Question

2. if ( a +b+c)(a -b +c)-a'+b + show that a, b, c are in continued proportion​

Answer 1

(a+b+c)(a−b+c)

=(a+b+c)(a+−b+c)

=(a)(a)+(a)(−b)+(a)(c)+(b)(a)+(b)(−b)+(b)(c)+(c)(a)+(c)(−b)+(c)(c)

=a2−ab+ac+ab−b2+bc+ac−bc+c2

=a²+2ac−b2+c²