Simplify 67c − 59d − 12 c + 13d.
We can simplify this expression by combining like terms.
The like terms of c are 67c and -12c.
The like terms of d are -59d and 13d.
Combining these terms, we get:
67c - 12c = 55c
-59d + 13d = -46d
Therefore, the simplified expression is 55c - 46d.