Question

If ×+1/×=19 find ײ+1/ײ​

Answer 1

✽ Question ✽

If x+1/x = 19, find x²+1/x².

✽ Given ✽

x+1/x = 19,

✽ To find ✽

x²+1/x²

✽ Formula to be used ✽

(a+b)² = a²+b²+2ab

✽ Solution ✽

x+1/x = 19

→ (x+1/x)² = 19²

→ x²+1/x²+(2×x×1/x) = 361

→ x²+1/x²+2 = 361

→ x²+1/x² = 361-2

→ x²+1/x² = 359

✽ Hence ✽

x²+1/x² = 359

✽ Therefore ✽

The value of x²+1/x² is 359.

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✽ More formulae ✽

• (a+b)² = a²+b²+2ab
• (a-b)² = a²+b²-2ab
• a²+b² = (a+b)²-2ab
• a²+b² = (a-b)²+2ab
• a²-b² = (a+b)(a-b)
• 4ab = (a+b)²-(a-b)²

◎ Hope this helps you. ◎