Advertisements
Advertisements
Question
If `3"x"+1/(3"x")=3`, find : `9"x"^2+1/(9"x"^2)`
Sum
Solution
`3"x"+1/"3x"=3`
`⇒(3"x"+1/"3x")^2=(3)^2`
`⇒(3"x")^2+(1/"3x")^2+2xx3"x"xx1/"3x"=9`
`⇒9"x"^2+1/"9x"^2+2=9`
`⇒9"x"^2+1/"9x"^2=9-2`
`⇒9"x"^2+1/"9x"^2=7`
shaalaa.com
Application of Formulae
Is there an error in this question or solution?
APPEARS IN
RELATED QUESTIONS
If a2 + b2 = 29 and ab = 10, find : a + b
If a2 + b2= 10 and ab = 3; find : a + b
If a + b + c = 10 and a2 + b2 + c2 = 38, find : ab + bc + ca
If a + b = 6 and ab=8, find : a3 + b3.
If a – b = 3 and ab = 10, find : a3 – b3.
Find : `"a"^3+1/"a"^3`, if `"a" +1/"a"=5`.
If `2"x"-1/(2"x")=4`, find : `4"x"^2+1/(4"x"^2)`
If a2 + b2 = 41 and ab = 4, find : a – b
If 3x – 4y = 5 and xy = 3, find : 27x3 – 64y3.
If 5x – 4y = 7 and xy = 8, find : 125x3 – 64y3.
