Question 3193
First, remember the equation of a line,<br>
y = mx + b<br>

where m is the slope of the line and b is the y-intercept.

The question tells you two points on the line. The first point is the x-intercept, we will call it P1 = (-1, 0), the second point is the y-intercept, which we will call P2 = (0, 4). We can find the slope of the line by <br>
m = {{{(y2-y1)/(x2-x1)}}} = {{{(4 - 0)/(0 - (-1))}}} = 4<br>
Since we already know the value of the y-intercept is 4, the equation of the line is:<br>
y = {{{4x + 4}}}<br>
<hr>
You can check this by setting x = 0, <br>
{{{y = 4*0 + 4 = 4}}} <br>

So we get the point (0,4) from this equation.<br>
Next set y = 0,<br>
{{{0 = 4x + 4}}} subtract 4 from both sides to isolate x<br>
{{{-4 = 4x}}} divide by 4 on both sides to get x by itself<br>
{{{-1 = x}}}<br>
This is the x-intercept (-1, 0) for the line. Our equation gives us the two points used to define the problem, therefore, it must be the correct equation.