name: Andrew, Student I am struggling with this problem: Could you please help me work out the value of x where: y = zx - x - c thanks a lot Andrew Hi Andrew, I am assuming that it is the lack of numbers in this problem that is causing you difficulties. I suggest that you replace z and c by numbers and see if you can solve the problem. Don't use the numbers 0, 1 or 2 but numbers like 3, 4, 5, ... I am going to let z = 3 and c = 7 and y = 5. Then the equation becomes 5 = 3x - x - 7. Solve for x. What I see here is 3x - x which is 2x and hence 5 = 3x - x - 7 5 = 2x - 7 Now add 7 to both sides to get 5 + 7 = 2x - 7 + 7 or 12 = 2x and hence, dividing both sides by 2, x = 6 Now can you mimic the steps I just went through but with z, c and y in the equation? As before, what I see is zx - x which is (z - 1)x and hence y = zx - x - c y = (z - 1)x - c Now add c to both sides to get y + c = (z - 1)x - c + c or y + c = (z - 1)x Finally, to find x, this time you need to divide both sides by (z - 1). x = y + c/(z - 1) Cheers, Penny Go to Math Central