Exercise 28 Page 343

Consider the given equation of a line. y=-x-9 ⟺ y=-1x+( -9) When lines are parallel, they have the same slope. Because of this, we know that all lines that are parallel to the line whose equation is given will have a slope of -1. We can write a general equation in slope-intercept form for these lines. y=-1x+ b We are asked to write the equation of a line parallel to the one with given equation that passes through the point ( 0, 5). By substituting this point into the above equation for x and y, we will be able to solve for the y-intercept b of the parallel line.

Now, that we have the y-intercept, we can write the parallel line to y=- x-9 through (0,5). y=-1x+ 5 ⟺ y=-x+ 5