Al P. answered • 11/24/19

Online Mathematics tutor

y = mx + b is called the **slope-intercept form of a line**. You will see this form a lot. In this formula, m is the slope (equal to the (change in y) / (change in x)), while b is where the line crosses the y-axis (the "y-intercept")

2x + y = 5 can be re-arranged to y = -2x + 5

By inspection, we can see -2 is the slope.

Parallel lines have equal slope. So we know the equation for the parallel line will have m=-2.

Another form for the equation of a line is the** point-slope** form: y-y_{0} = m (x - x_{0})

where m=slope and (x_{0},y_{0}) is a point that the line passes through.

y - 1 = -2 (x - 3)

**y = -2x + 7**

Check: -2(3) + 7 = -6 + 7 = 1 so y=1 when x=3. Yes, the line passes through (3,1)