### Complex Partial Fractions

To break down an algebraic fraction into partial fractions in which all the denominators are linear and all the numerators are constants you sometimes need complex numbers.

### Agile Algebra

Observe symmetries and engage the power of substitution to solve complicated equations.

# Graphs of Changing Areas

##### Age 16 to 18 Challenge Level:

How does the rectangle with length $x$ and width $y$ relate to the rectangle with width $x$ and length $y$?