Parallel lines have the same slope.
So I plug in the -5 and -4
-4 = 1/2(-5) + b
-4 = -2.5 + b
b = -1.5
So I get y = 1/2x - 3/2
97. The great wall is more than 20 000 kilometers long. And about ¾ of it is considered as properly preserved.
I guess you are asking about the value of ¾ which is properly preserved in the said length of the great wall.
=> ¾ = 0.75
Thus, the formula would be like this:
=> 20 000 * .75 = 15 000
Thus, the ¾ value of great wall that is preserved is equals to 15 000 kilometers long,