How do you write an equation in slope intercept form given a slope and a x-intercept?

1 Answer

What is x-intercept? It is such an argument (x-value) where y-value equals 0. In equations you would tell that it is root of the equation.

In general formula #y = mx+b# you insert known information, where #m# is a slope (or gradient) and #b# is free-term (or y-intercept - such an value where function cuts y-axis, so point (0, b) ).

Let us take example. You are given slope - it is 2. And you know that your x-intercept is equal 3. Therefore, you know that when #x = 3#, #y=0#.

Let us use that information. You know that you may write every linear function like that: #y = mx+b#.
Let us insert values: #0 = 2*3+b#
Our unknown is #b#, free term. Let us isolate it:
#b=-6#.
And after all, we must insert our #b# value back into equation: #y = 2x - 6#.