Equations and inequalities notes

This document contains notes for equations and inequalities. They should be very useful while working with equations and inequalities.

• You can solve linear simultaneous equations by elimination or substitution.
• You can use the substitution method to solve simultaneous equations, where one equation is linear and the other is quadratic. You usually start by finding an expression for x or y from the linear equation.
• When you multiply or divide an inequality by a negative number you need to change the inequality sign to its opposite.
• To solve a quadratic inequality you;
  • solve the corresponding quadratic equation, then
  • sketch the graph of the quadratic function, then
  • use your sketch to find the required set of values.