Higher - The gradients of two perpendicular lines will always multiply to make –1. Make sure you are familiar with finding the equation of a line and calculating gradient to understand equations of ...

The use of concrete models for teaching students how to solve equations is often debated in scientific literature. This article aims to examine the balance model and to identify the issues that divide ...

"Even the +, −, =, and x signs we take for granted only came into widespread use in the 17th century. Which means that the earlier algebraists we know of … all had expressed their equations mostly in ...