Use of MathsLinear models

Equations of straight linesFinding gradients

Aims

Recap from lesson 1

Developing linear models

The equation of a straight line

Recap

The equation of a straight line

All straight lines have an equation of the form y = mx + c

m is the gradient of the line c is the y-intercept

Find the gradient and y-intercept for y= 4.8x - 6.9

Fill the gaps

Equation Gradient y-intercepty = 3x + 1y = - 0.4x - 0.8

2.1 -0.730 3.1

y = 6.2y + x = 5.2

y = mx + c

Re-arrange the following equations into the form y = mx + c and hence state the gradient and intercept with the y-axis

2x + y = 4

3x + y = -6

x + y = 7

2x + 2y = 6

Sketching linesSketch the following straight line graphs

y = 2x + 6

y = - x + 6

y = 6

x = 9

Sketching lines using mini-white boards

y = x

y = x + 2

y = 2x + 4

y = -2x + 1

y = 2.1

x = 3.2

Finding the gradient from the graph

Gradient = distance up divided by the distance across

Gradient = distance updistance across

Gradient = riserun

Find the gradients of these lines

Booklet Ex 1