Answer:
To find the value of "c" for which the number "a" (-5 in this case) is a solution of the equation, we can substitute "a" into the equation and solve for "c".
Given equation: 4x + 1 + 7c = 8c - 3x + 6
Substituting x with "a": 4(-5) + 1 + 7c = 8c - 3(-5) + 6
Simplifying the equation: -20 + 1 + 7c = 8c + 15 + 6
Combining like terms: -19 + 7c = 8c + 21
Moving all "c" terms to one side: 7c - 8c = 21 + 19
Simplifying: -c = 40
Dividing both sides by -1 to isolate "c": -c/-1 = 40/-1
Flipping the sign when dividing by a negative number: c = -40
So, the value of "c" for which the number "a" (-5) is a solution of the equation is c = -40.