Plz help Solve using subtitution method:
2(x^2 +1/(x^2)) - 11(x-1/x) +8=0

As far as I know, by substitution method, it means to take a part of the equation, for example x+1/x, and make it into another variable.

Aheated piece of metal cools according to the function c(x) = (.5)x ? 7, where x is measured in hours. a device is added that aids in cooling according to the function h(x) = ? x ? 2. what will be the temperature of the metal after two hours?

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

The square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base