In order for someone to write a linear equation, they need some information about the line. For example, here are a few info combinations where writing a linear equation is possible:
- Slope + Y-intercept (solution: plug in values)
- Slope + 1 coordinate point that the line goes through (solution: increase or decrease coordinate by slope value until x = 0 to find y-intercept)
- 2 coordinate points (solution: find slope and do the same as step 2 to find y-intercept)
- 1 coordinate point and the equation of a line that's parallel/perpendicular to the other line (Parallel solution: plug in the slope of the other line and repeat step 2 to find y-intercept. Perpendicular Solution: get negative reciprocal of the slope of the other line and repeat step 2 to find y-intercept)
Is there any other info or info combinations that could be involved? This is a little hard to explain so if it's unclear, please tell me in the comments.