Given 2x+3y=225
either we can solve it for x or y
if we solve it for x
=>2x=225-3y
=>x=(225-3y)/2
if we solve it for y
=>3y=225-2x
=>y=(225-2x)/3
Algebra Linear Equations - http://math.tutorvista.com/algebra/linear-equations.html
Linear equation is a condition on a variable. A variable takes on different values; its value is not fixed. Variables are denoted usually by letter of alphabets, such as x, y, z, l, m, n, p etc. Linear equations in one variable is the type of equation which have unique (i.e, only one and one) solution.