Question

If a : b = c : d, prove that :
(6a + 7b)(3c - 4d) = (6c + 7d)(3a - 4b).​

Answer 1

Answer:

Step-by-step explanation:

let,

a/b=c/d=k

it means, a=ck and b=dk

LHS,

(6a+7b)(3c-4d)

= {6×ck+7×dk}×{3×c-4×d}

=k×(6c+7d)×(3c-4d)

=k×(18c^2+21cd-24cd-28d^2)

=k(18c^2-3cd-28d^2)

RHS,

(6c+7d)(3a-4b)

=(6c+7d)(3×ck-4×dk)

=k×(18c^2+21cd-24cd-28d^2)

thus,

we can say,

LHS=RHS