GCSE Maths


In the algebra section, we looked at how we can use letters as numbers and how to find their values. There are times, however, when life gets a little harder:

x + y = 25

We cannot say what x and y are in the equation above because there are an infinite number of possibilities:

x = 1, y = 24
x = 21, y = 4 etc.

In general, a single equation with two unknowns (we don't know x and y in this case) cannot be solved. What we need is a second equation involving at least one of the unknown variables.

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