Point-slope form is a different type of way to write a linear equation than slope-intercept (y=mx+b). Point-slope is in this form: y-ypoint=m(x-xpoint)
Point-slope uses a point and the slope (namesake) to make an equation and can be converted to slope-intercept form. For example, if (4, 2) is my point and 2 is my slope, then point-slope form would be y-2=2(x-4). (This can then be solved for y to get slope-intercept)
Remember to use the same point when plugging in for your x and y in the equation, never use two different points.