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Starter Questions. Factorise 5x + 10. The Straight Line Equation. Learning Intention. To explain and draw straight lines of the form y = mx + c. By calculating the gradient of each line, write down the equation of the line. The Straight Line Equation. y. 1. 2. 4. 3. 5. x.
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Starter Questions Factorise 5x + 10
The Straight Line Equation Learning Intention • To explain and draw straight lines of the form y = mx + c.
By calculating the gradient of each line, write down the equation of the line The Straight Line Equation y 1 2 4 3 5 x
The Straight Line Equation Gradient = vertical height horizontal distance Line 1 = 4 1 = 4 Equation of line is y = 4x Gradient = vertical height horizontal distance Line 2 = 3 2 Equation of line is y = 3x 2 Gradient = vertical height horizontal distance Line 3 = 2 2 = 1 Equation of line is y = x
The Straight Line Equation Gradient = vertical height horizontal distance Line 4 = 1 2 Equation of line is y = 1x 2 Gradient = vertical height horizontal distance = 1 4 Line 5 Equation of line is y = 1x 4
The Straight Line Equation All the lines we have previously looked at all passed through the origin at (0,0) i.e. y = 2x, y = 3x, y = ½x, y = 5x etc… Gradient = 3 Gradient = 5 Gradient = 2 Gradient = ½ What about straight lines that do not pass through the origin
The Straight Line Equation Example Draw the line of y = 2x on a suitable coordinate diagram y = 2x + 2 y x 0 1 2 3 4 Same gradient, but slightly higher up 8 0 2 4 6 y y = 2x On the same diagram, draw the graph of y = 2x + 2 x 0 1 2 3 4 2(0)+2 2(0)+2 2(0)+2 2(3)+2 2(4)+2 y =2 =4 =6 =8 =10 x What do you notice about the second line?
The Straight Line Equation Example Draw the line of y = x on a suitable coordinate diagram y y = x + 4 x 0 1 2 3 4 Same gradient, but slightly higher up 4 0 1 2 3 y y = x On the same diagram, draw the graph of y = x + 4 x 0 1 2 3 4 8 4 5 6 7 y x What do you notice about the second line?
y 10 9 8 7 6 5 4 3 2 1 x 0 -10 1 2 3 4 5 6 7 9 10 -9 -8 -6 -4 -3 -2 8 -7 -5 -1 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 y = x On your 4 quadrant diagram, Draw the lines of the given equations. The Straight Line Equation x y 0 2 4 y = 3x+1 0 2 4 x y 2 0 1 1 4 7 y = 2x + 3 y = x - 3 x y x y 8 0 4 0 1 2 -3 1 5 3 5 7
Straight Line Equation y 10 All straight lines have the equation of the form lines are parallel if they have the same gradient 9 8 y = mx + c 7 6 5 4 3 Where line meets y-axis 2 Gradient 1 x 0 10 1 2 3 4 5 6 7 8 9 Find the equations of the following lines y = -0.5x+2 y = x y = x+4 y = 4x+2
Straight Line Equation Now try Ex 4 Ch6 Page 73 Start at Q4