Use the slider to explore worked examples.

Worked Example

The length of a metal rod is \(l\) cm. The length changes with temperature and can be found by the formula:
\(l = 40 + 0.02T\) where \(T\) is the temperature.
Find the length of the rod when \(T = 50^\circ\)C
Worked Example

The profit in £ made by a salesman when he sells \(n\) books is calculated by the formula:
\(P = 4n − 50\)
Find the profit if he makes \(30\) sales.
Worked Example

If \(z = x^{2} − 4y^{2}\) what is the value of \(z\) when \(x = 4\) , \(y = −2\) ?

Formulae