Linear Equations in Two Variables — Quick Revision
A linear equation in two variables has the standard form ax + by + c = 0 where a and b are not both zero. A solution is an ordered pair (x, y) that satisfies the equation, and every such equation has infinitely many solutions. When plotted, all the solutions lie on a straight line, so the graph of a linear equation in two variables is always a line. The equation y = mx passes through the origin, x = a is a line parallel to the y-axis and y = b is a line parallel to the x-axis.
Key Points
- •Standard form: ax + by + c = 0 (a, b not both zero)
- •A solution is an ordered pair (x, y)
- •Infinitely many solutions
- •Graph is always a straight line
- •x = a ∥ y-axis; y = b ∥ x-axis