The slope-intercept form of the equation of a line is y = mx + b, where m is the slope of the line and b is the y intercept. To solve for y, multiply the x value by the slope, then add the y-intercept. To solve for x, subtract the y intercept from the y value, then divide it by the slope.
- Determine the slope of the straight line
Take the coordinates (x,y) of two points on the line. Divide the difference of the two y values by the difference of the two x values to get the slope.
- Look for the y-intercept
The y-intercept is the y value of the point on the line where x = 0. This point is where the line meets the vertical y axis. Look for the point, and determine the y-value.
- Substitute the values to the equation y = mx + b
Use the slope as the value of m and the y intercept as the value of b.
- Solve for the missing value
If you have an x value, substitute the x with that, then solve for y. If you have a y value, substitute the y with that value, then solve for x.