First to answer and get right gets brainleist and there is ma points pls help

Answer:
#11 is D. x = u - k
#12 is D. x = gc
Step-by-step explanation:
I plugged random integers to test this. Anyhow, just do the inverse operation.
#11:
13 = x + 8
x = 13 - 8
x = 5
Here, x = u - k is the new equation.
#12:
23 = x/9
x = 23(9)
x = 207
Here, x = gc is the new equation.