what is 2x7<18

Did you mean:       2x^7 < 18?

If so:  divide by 2:   x^7 < 9

Find the 7th root:        x < (9)^(1/7)

Approximately:            x < 1.3687

2*7<18 is 14<18?  I don't get what you mean.

If you really meant 2*7<18 then, as a Boolean expression, it is true.

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