Question

49. ( (4) x^{4}+frac{1}{x^{4}}=23 )
( Rightarrowleft(x^{2}+frac{1}{x^{2}}right)^{2}-2=23 )
( Rightarrowleft(x^{2}+frac{1}{x^{2}}right)^{2}=23+2=25 )
( therefore x^{2}+frac{1}{x^{2}}=5 )
( left(x-frac{1}{x}right)^{2}=x^{2}+frac{1}{x^{2}}-2 )
( =5-2=3 )

# 49. If **+ * = 23, then the val- ue ue of (x - ) will be will be (1) 7 (3) - 3 (2) - 7 (4) 3

Solution