If an equation has a single unknown, we can usually solve it


x + 5 = 15 x = 10

However if an equation has two unknowns, it is usually impossible to solve.


3x + 4y = 22

There are infinite combinations of x and y that could be substituted into this equation to give 22, and so there is no single solution for the value of x and y.

For example, substituting the following into the equation will all produce 22

x = 0, y = 5.5

x = 22/3, y = 0

x = 2, y = 4

If we are provided with a second equation, however, then there will be only a single solution (if both equations are linear)

3x + 4y = 22

-2x + 4y = 12

There is now only a single solution for x and y that will produce both 22 in the first equation, and 12 in the second: x = 2, y = 4.

To solve the simultaneous equations graphically is fantastically easy to solve

Plot the two equations See where they cross – the coordinates where the two graphs cross are the solutions for x and y

The graphs will cross only once if both are linear. If one of them is non-linear, then they may cross once, twice, or sometimes not at all.

Improve this description

Nothing in this section yet. Why not help us get started?

Improve the Test Questions

Related Topics

2Simple software
Taking IT global

Related Questions

All related questions