Question

x²-1/x=7 find x²+1/x²
please line by line explanation ​

Answer 1

(a-b)² = a²+b²-2ab

Using this formula-

x-1/x = 7

or, (x-1/x)² =  7²      { squaring both sides}

or, (x²+1/x²-2×x×1/x) = 49

or, x²+1/x²-2 = 49

or, x²+1/x² = 49+2

or, x²+1/x² = 51

Hence, x²+1/x² = 51.

Hope this helps you to get to your answer.