So many students will solve this problem by taking the product of numerator & the product of Denominator & then take the division. I had done this problem with the different method of calculations which is very simple, saves your valuable time and authentic also.
[Here Students must take the complete square of 28 and 21 and the product of 28 and 21 as shown below
[Multiplying Numerator & denominator by 7 write down the addition of all three terms of the square bracket]
[Then the student will divide numerator and denominator by 7 and write the results]
[Here modify the term of the denomination using the formula [r12 + r22 – 2 x r1 x r2 = (r1 - r2) 2. so we can write [r12 + r22 + (r1 x r2)] = r12 + r22 – 2 x r1 x r2 + 2x r1 x r2 + r1 x r2] so we have]