If m and n are real numbers, i^2=-1, and (m-n)-4i=7+ni, what is the value of m?

(m-n)-4i=7+ni

m = 7 + ni + n + 4i

To find the value of m, we will equate the real parts and imaginary parts of the given equation.

Given equation: (m - n) - 4i = 7 + ni

Equating the real parts:
m - n = 7

Equating the imaginary parts:
-4i = ni

Since the imaginary parts are equal, we can equate the coefficients of i:

-4 = n

Now, substituting n = -4 into the equation m - n = 7, we can solve for m:

m - (-4) = 7
m + 4 = 7
m = 7 - 4
m = 3

Therefore, the value of m is 3.