Words to equation
A standard method from Variations: the steps.
Steps
| Statement | Equation |
|---|---|
| y varies directly as x | y = kx |
| y varies directly as x² | y = kx² |
| y varies inversely as x | y = k/x |
| y varies jointly as x and z | y = kxz |
| y varies directly as x and inversely as z | y = kx/z |
| y is partly constant and partly varies as x | y = a + bx (two constants) |
| y partly varies as x and partly as x² | y = ax + bx² |
For the whole topic, read Variations: key points, common mistakes and how the DSE tests it.