Why are you using C and c for the obvious same variable ??
my steps:
c+9-3(c-10)>1
c + 9 - 3c + 30 > 1
-2c + 39 > 1
-2c > -38
divide both sides by -2, recall that when multiplying or dividing by
a negative, we must reverse the inequality sign
c < 19
I have copied your steps and marked the lines containing errors based on the previous lines with **
c+9-3(c-10)>1
Here’s what I’ve got so far:
C+9-3(c-10)>1
C+9-3c-30>1 **
C-21-3c>1
C-21-3c+21>1-21 **
C-3c>-20
C-3c-c>-20-c , why?
3c>-20 **
3c/3>-20/3 **
Answer: c>-6.66 **
You seem very confused.
The rules for inequations are the same as those
for equations, EXCEPT for the part about multiplying or dividing both sides by a negative. This usually only happens in the very last step in your solution.