Question 227045
Their are 2 ways to solve this problem.<br>

Method 1.  Using the slope-intercept formula of a line.<br>

We know that the equation of a line in slope interecept form is y=mx+b where m is the slope and b is the y intercept.  Since we have the slope and a point we could plug those in and solve for b.<br>

y = mx+b
-9 = 7(-9)+b
-9 = -63+b
54 = b<br>

So we know the y-intercept is at 54.<br>

Method 2.  Using the point slope formula.<br>  

There is another equation that will give us the equation of a line.  Its y-y1=m(x-x1).  Where (x1,y1) is the given point and m is your slope.<br>

Plugging in the values we have we get:<br>

y-(-9) = 7(x-(-9))
y + 9 = 7(x+9)
y = 7x+63-9
y = 7x+54<br>

SO we know that the y-intercept is 54.  <br>


Either method you use will get you the right answer.