Solving Equations with graphs

Solving Equations with graphs

Understanding Graphs and Equations

  • An equation allows you to express the relationship between different quantities. It is typically shaped like “x = y”.
  • An equation becomes a linear equation when the highest power of the variable is one. They form straight lines when plotted on a graph.
  • Non-linear equations are equations where the variable has a power greater than one or less than one. The graph of a non-linear equation is typically a curve.

Plotting Points and Drawing Graphs

  • Points on a graph are typically labelled with an x-value (horizontal or ‘along’) and a y-value (vertical or ‘up’).
  • When drawing a graph, start by plotting a few key points and then join them up.
  • The point where the graph meets the x-axis is known as the x-intercept. When the graph intersects the y-axis, it’s called the y-intercept.

Using Graphs to Solve Equations

  • The solution to an equation is the value or set of values which makes the equation true.
  • If solving a linear equation, the solution will be the point where the line crosses the x-axis.
  • In non-linear equations, there can be more than one solution. The graph will cross the x-axis at each solution.
  • When two lines intersect on a graph, the coordinates of the point of intersection provide the solution to the system of equations represented by the two lines.

Types of Graphs

  • Linear graphs are straight lines which usually have the equation ‘y = mx + c’. Here, ‘m’ is the gradient and ‘c’ is the y-intercept.
  • A graph that forms a curved line, typically represented by the equation ‘y = x^2’, is a quadratic graph.
  • Cubic graphs will have one variable to the power of three and generally take shape as a curve with a single or double bend.

Reading and Interpreting Graphs

  • Being able to read and interpret a graph is essential. The scale, labels, and units provide key information about what a graph is representing.
  • The gradient of a line reflects how steep it is, and can be found by dividing the vertical change by the horizontal change.
  • As well as finding solutions, graphs can also be useful for comparing data, spotting patterns, and predicting outcomes.

Study, practise, and be sure to understand these concepts to improve your problem-solving skills in Mathematics.