kimiya has 4x marbles ramneet has x marbles then 4x - 18 = x + 18 because if you give 18 marbles from kimiya to ramneet then you subtract 18 from kimiya and add 18 to ramneet by solving the equation you will get x as 12.So kimiya has 48 marbles, ramneet has 12 marbles.
Every linear graph is just a straight line, so if there are any curves or unnatural shapes, than you know it is not linear. As for equations, if it can be shaped into y=mx+b where m and b are numbers, then it will be a linear equation.
