Two pens and a notebook cost 10 dollars. Which prices are possible? An equation with two unknowns has many answers. In this course we learn to find them, and we draw them all as one straight line.
3 lessons, about 1 h 15 min3 simulations9 problems6 practice questionsPython in every lesson
A linear equation in two variables has the form ax plus by plus c equals 0, where a and b are not both zero, and both variables have the power 1. A solution is a pair x, y that makes the equation true. Such an equation has infinitely many solutions: choose a value of x, and y is decided. We can check whether a pair is a solution by putting it in the equation, and we can write the equation to give y in terms of x. Equations like temperature conversion, cost of pens and notebooks and the perimeter of a rectangle are examples. In a shop problem, some solutions are not valid, for example a negative price.
Every solution is a point. All the points of the solutions of a linear equation lie on one straight line.
Lines parallel to an axis, lines through the origin, and a line that tells a story, like a taxi fare.
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