Question

prove that (7ab+1/3)2-(7ab-1/3)2 =28ab/3​

Answer 1

Step-by-step explanation:

(7ab+1/3)²-(7ab-1/3)²=98ab/3

using (a+b)²and(a-b)²

proving LHS

[(7ab)²+2(7ab)(1/3)+(1/3)²] -[(7ab)²-2(7ab)(1/3)+(1/3)²]

49a²b²+49ab/3+1/9-[49a²b²-49ab/3+1/9]

49a²b²+49ab/3+1/9-49a²b²+49ab/3-1/9

49ab/3+49ab/3

98ab/3=98ab/3

hence LHS=RHS

The question you have given was almost correct RHS should be 98ab/3 not 28ab/3 , might be copying mistake .

hope this answer is helpful for you