Add -15c and 7c since they have the same variable. After that you get a negative answer so you add the answer to both sides. That will cancel both numbers so it will be 1=3, the answer will be false.
Add like terms -15c+7c=7c-15c=-8c we can't add the c terms and the numbers so we leave it so -8c+1=3-8c add 8c to both sides 8c-8c+1=3+8c-8c 0+1=3+0 1=3 false there is no solution
