Answer:
a. 5cm
Step-by-step explanation:
r. m+m+n+n= 34
t. m+n+n+1=30
r. 2m + 2n =34
t. m + 2n + 1 = 30
after multiple by negative t row
t. -m -2n -1 = -30
and combine the 2 rows
2m -m +2n - 2n -1 = 34 - 30
m - 1 = 4
and we add one to each side of the operation
m - 1 + 1 = 4 + 1
m = 5
