Linear equations ( slope -intercept form)

The first of the forms for a linear equation is slope-intercept form.

Y = MX + b is slope-intercept form
where M is the slope or gradient of the line and b is the y-intercept of the line, or the y-coordinate of the point at which the line crosses the y-axis.

Example : In y = 2x + 9 ,slope 2 and y intercept is 9.
Practice: find slope and y intercept of the equations
y = 5x + 12
y = 8x + 5
y = 7x + 4

Answers:
slope = 5 and y intercept = 12
slope = 8 and y intercept = 5
slope = 7 and y intercept = 4

Example: write the equation of line whose slope is 5 and y intercept is 2
y = 5x + 2

practice: write the equation of line
slope = 4 & y intercept =7
slope = 2 & y intercept =9
slope = 5 & y intercept = -12

Answers:
y =4x + 7
y =2x + 9
y =5x - 12

Example : Write an equation of the line with slope m = 6 which crosses the y-axis at (0, 5). (here y intercept is 5, because x coordinates is 0)
y = 6x + 5

practice:
Write an equation of the line with slope m = 3 which crosses the y-axis at (0, 4).
Write an equation of the line with slope m = -5 which crosses the y-axis at (0, 9).
Write an equation of the line with slope m = 1/2 which crosses the y-axis at (0, 3/2).

Answers:
y = 3x + 4
y = -5x + 9
2y = x =3