Firstly I would try to learn about the students abilities and maybe do an easier linear equations (without brackets) to ensure they have a basic idea how to solve these types of equations. For this questions I would ask them to:
expand the brackets firstly 10c - 15 = 19
add/subtract numbers so that the equation is in the format 10c = ?
so in this case I would get them to add 15 to 19 (as a minus number becomes a plus as it travels across the equals sign)
so 10c = 34
then I would explan how there are 10 'c's' making up 34 so you then have to divide 34 by 10 to find the value of c
c = 34/10 = 3.4