Respuesta :
Answer:
Step-by-step explanation:
1/2(-9+n)=20
n=40+9
n=49
Answer:
49
Step-by-step explanation:
Sum means add
-9+n
Multiply this by 1/2
1/2(-9+n)
This is equal to 20
1/2(-9+n) = 20
Solve
Multiply each side by 2 to get rid of the fraction
2*1/2(-9+n) = 20*2
-9+n = 40
Add 9 to each side
-9+9 +n = 40+9
n = 49