Maths
Maths Puzzle
Numerical Ability
Arithmetic
(7+√15)^x+(7-√15)^x=128 find x?
Read Solution (Total 2)
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- (7+15^(1/2))^2 + (7-15^(1/2))^2 = 49 +2*7*(15^(1/2)) +15+49 -2*7*(15^(1/2)) +15 =128 so,
x=2 - 10 years agoHelpfull: Yes(1) No(0)
- we know x=2 but how?
- 10 years agoHelpfull: Yes(0) No(0)
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