Answer:
m = 5 and n = 6
Explanation:
In a parallelogram, opposite sides of the figure are congruent (equal to each other).
This means that 3m - 7 = m + 3 and 2n + 12 = 4n
We can now solve for the variables
3m - 7 = m + 3
==> add 7 to both sides
3m = m + 10
==> subtract 2 from both sides
2m = 10
==> divide both sides by 2
m = 5
2n + 12 = 4n
==> subtract 2n from both sides
12 = 2n
==> divide both sides by 2
6 = n