Someone all the questions r attached as well as the

The error is in Step-4.

A negative exponent does NOT mean that the number turns negative. A negative exponent means the number is in the denominator.

(4)⁻⁴ means (1/4⁴) .  That's (1/256) .  All positive numbers.

1 number

if we use a graphing calculator, there is only one such number that satisfies the conclusion of the mean value theorem, that is, a number such that

where the right-hand side is the average rate of change of f on the interval [0.5,0.75], which is the slope of the secant line.

in the attached graph, the black line is the secant line which has its slope as the average rate of change of f on [0.5,0.75], while the orange line is the only tangent line to the graph of f in the interval that satisfies the mvt conclusion.