What is the slope-intercept form of the line passing through # (-2, -1)# and #(-1, 7) #?

1 Answer
Dec 17, 2015

Answer:

#y=8x+15#

Explanation:

The slope-intercept form of a line can be represented by the equation:

#y=mx+b#

Start by finding the slope of the line, which can be calculated with the formula:

#m=(y_2-y_1)/(x_2-x_1)#

where:
#m=#slope
#(x_1, y_1)=(-2, -1)#
#(x_2, y_2)=(-1, 7)#

Substitute your known values into the equation to find the slope:

#m=(y_2-y_1)/(x_2-x_1)#

#m=(7-(-1))/(-1-(-2))#

#m=8/1#

#m=8#

So far, our equation is #y=8x+b#. We still need to find #b#, so substitute either point, #(-2,-1)# or #(-1,7)# into the equation since they are both points on the line, to find #b#. In this case, we will use #(-2,-1)#:

#y=8x+b#

#-1=8(-2)+b#

#-1=-16+b#

#b=15#

Substitute the calculated values to obtain the equation:

#y=8x+15#