Show that the positive root of the equation 1/x = x + 3 lies in the interval (0.30, 0.31).

From the sketch I found two intersection points. One in the +ve axis & another in the –ve axis. And I found sign change by substituting f(0.3) & f(0.31). But in the question says Show that the positive root of the equation, is it mean f(x) = 1/x – x - 3?

If there is a question about to show that the negative root of the equation, then what to do?