Question

How do you determine the y-intercept and the x-intercept in an algebraic equation? I'm trying to figure out how to tell which is which. I already know the rule; y=mx+b

Answer 1

If you want to find the x-intercept, you replace y in the equation with 0 and solve the equation for x.
If you want to find the y-intercept, you replace x in the equation with 0 and solve the equation for y.

Example:

`y=2x+5\\\\ \hbox{x-intercept}\\ 0=2x+5\\ 2x=-5\\ x=-2.5\\ \hbox{x-intercept is } (-2.5,0)\\\\ \hbox{y-intercept}\\ y=2\cdot0+5\\ y=5\\ \hbox{y-intercept is }(0,5)`