Question

y²+1/y²= 6 find the value of y-1/y.​

Answer 1

(y +  \frac{1}{y} ) = 4 \\  \\  \\ (y +  \frac{1}{y} ) {}^{2}  = 4 { }^{2}  \\

(y +  \frac{1}{y} ) {}^{2}  = 16

Expanding it ....

y {}^{2}  +  \frac{1}{y {}^{2} }  + 2 = 16

y {}^{2}  +  \frac{1}{y {}^{2} }  = 14

Answer 2

Answer:

=(y-1/y)^2. {since (a+b)^2=a^2+b^2+2ab}

=y^2+(1/y)^2-2×y×1/y

=y^2+1/y^2-2

since y^2+1/y^2=6

=6-2

=4 ans.......