If 𝑚 is in Quadrant I and tan2𝑚 = 24/7 then the value of tan𝑚 is:

you have

y=24
x=7
so r = 25 (the familiar(!) 7-24-25 triangle)
That gives you
sin 2m = y/r = 24/25
cos 2m = x/r = 7/25
and now you can use the half-angle formula to find tan m

tan ( 2 θ ) = 2 tan θ / ( 1 - tan² θ )

tan ( 2 θ ) = 24 / 7

2 tan θ / ( 1 - tan² θ ) = 24 / 7

Divide both sides by 2.

tan θ / ( 1 - tan² θ ) = 12 / 7

Cross multiply.

tan θ • 7 = ( 1 - tan² θ ) • 12

7 tan θ = 12 - 12 tan² θ

Add 12 tan² θ to both sides.

12 tan² θ + 7 tan θ = 12

Subtract 12 to both sides.

12 tan² θ + 7 tan θ - 12 = 0

Mark tan θ as x

12 x² + 7 x - 12 = 0

The solutions are:

x = - 4 / 3 and x = 3 / 4

Since x = tan θ the solutions are:

tan θ = - 4 / 3 and tan θ = 3 / 4

In Quadrant I all trigonometric functions are positive, so:

tan θ = 3 / 4