Y intercept • To find the y-intercept, plug 0 in for x in the linear equation and solve for y. • y=3x-6 (0, -6)
Y intercept • The y-intercept is the point where a line crosses the y axis. • At this point the value of x is 0.
Slope • y=3x-6 • To find the slope first find 2 points. • (2, 0) and (0, -6) • Then substitute in and solve
Slope Intercept Form • y=mx + b • m is the slope • b is the y-intercept
Slope Intercept Form y=3x-6 The slope is The y intercept is
Slope Intercept Form To graph y=3x-6 • Plot (0, -6) • then count slope • Up 3 right 1 • Connect your points to make a line.
Writing an Equation Write the equation of the line with slope 3/8 and y-intercept 5. Use slope intercept form: y=mx+b Substitute in for m and b
You Try Write the equation of a line with slope -.5 and y-intercept -3 Write the equation of a line with slope 4 and y-intercept -5/2.
You Try Identify the slope and y intercept. y = -5x + 13 Slope: Y-Intercept: Identify the slope and y intercept. y = 1/4x – 2 Slope: Y-Intercept:
Writing an Equation Write the equation of the line with slope 2 That passes through pt. (1, 4). • Use slope intercept form: y = mx + b • Substitute in for m • Substitute in your points values for x and y • Solve for b • Use slope intercept form and substitute in b and m
You Try Write the equation of a line with slope -3 that passes through pt. (2, 5)
Writing an Equation Given 2 Points • Write y=mx+b • Calculate the slope using: • Substitute for m • Substitute one of the given points for x and y • Solve for b • Rewrite the equation using the calculated values for m and b