Question

初二数学题11

若x＋1/x＝3，则x²＋1/x²的值为_____
写出·计算过程方法这道题很难理解

Answer 1

x + 1/x = 3
(x + 1/x)² = 9
x² + 2 + 1/x² = 9
x² + 1/x² = 7

Answer 2

X²+1/X²
=X²+1/X²+2X²*1/X²-2X²*1/X²
=(x+1/x)²-2X²*1/X²
=9-2
=7

Answer 3

x²＋1/x²=（x＋1/x）²-2＝3²-2=7

请采纳

Answer 4

望一定采纳   谢谢

Answer 5

（X+1/X）^2=9, X^2+2+1/(X^2)=9 得出结果为7 望采纳。