Question: Write the equation of the line in slope-intercept form. Through the points (-8, 15) and (6, 15)
Solution:
The equation of the line in slope-intercept form is :
y = mx + b
where m is the slope of the line, and b is the y-coordinate of the y-intercept of the line. Now, the slope of the line is given by the following formula:
[tex]m\text{ = }\frac{Y2-Y1}{X2-X1}[/tex]Where (X1,Y1) and (X2,Y2) are points on the line. In our case, we have that:
(X1, Y1) = (-8,15)
(X2,Y2) = (6,15)
Replacing these values in the equation of the slope we obtain:
[tex]m\text{ = }\frac{Y2-Y1}{X2-X1}\text{ =}\frac{15-15}{6-(-8)}\text{ = 0}[/tex]then we have a horizontal line, because the slope is 0, for that, the equation of the line would be:
y = mx + b = 0(x) + b
then
y = b
now, take any point on the line, for example (x,y) = (6,15). Replacing this value in the previous equation, we obtain that the equation of the line is given by:
[tex]y\text{ = 15}[/tex]