4=2m-5n

m is 7

N is 2
so 4= 2 x 7 - 5 x 2

To solve the equation 4 = 2m - 5n, we need to isolate either variable (m or n) and find its value. Let's solve for m:

Step 1: Bring the -5n term to the other side of the equation by adding 5n to both sides:
4 + 5n = 2m

Step 2: Divide both sides of the equation by 2 to isolate m:
(4 + 5n) / 2 = m

Therefore, the solution to the equation 4 = 2m - 5n is m = (4 + 5n) / 2.

Your solution of

m is 7
N is 2
is not unique, how about
m=12, n=4 OR m=2, n=0, OR m=-3, n=-2, OR ....

There would be an infinite number of solutions.