1. Maths Graphs & Equations
GCSE Revision 101
Maths
Graphs & Equations
© Daniel Holloway

2. The Basics
We know that all linear graphs appear in the form y = mx + c where m is the gradient of the line and c is the point at which the y-axis is intercepted

3. The Basics Suppose we wanted to find the equation of the line shown:
Find the point where the line crosses the y-axis in this case, it is (+)2 therefore, c = 2
Find the gradient of the line in this case, it is (+)3 therefore, m = 3
Put the two pieces of information together the equation: y = 3x + 4 y 5 -5 5 x

4. The Basics Give the equations of the following lines: Equation:y 5
Equation:
y = 1.5x
y = 5x + 1
y = ⅓x - 1 -5 5 x

5. Simultaneous Equationsy
We can solve simultaneous equations graphically as well as algebraically. We simply need to use the same m and c rules to plot the lines and find where the points meet 5 O 5 x

6. Simultaneous Equationsy
Take the simultaneous equations
y = x + 5
y = 2x + 4
This is how we can solve the pair of equations graphically 5 O 5 x

7. Simultaneous Equations
y = 2x + 4
y = x + 3 y
1. Plot points and draw in the line for one equation
2. Complete the same for the other equation 5
The point at which the two lines cross is our answer. Read the x and y values on the grid to find:
x = 1
y = 6 O 5 x