Question

how do find the x-intercept of a line using just 2 points given?

Answer 1

you know that the equation of a line is \[y=ax+b\]the slope is a
the y-intercept is b
the x-intercept is -b/a
suppose you have 2 points (x1,y1) and (x2,y2) found on the line.
if you replace (x1,y1) and (x2,y2) in the above equation you will get
a=(y2-y1)/(x2-x1)
\[b=(y1\times x2-x1 \times y2)/(x2-x1)\]
you can now compute -b/a which is the x-intercept