While this may seem confusing at first, it's much more simple than it will ever appear. Given we have a total length, 4x + 1, and a segment length, 3x - 4, we just need to subtract the given segment from our total to solve for our other segment.
(4x + 1) - (3x - 4); we cannot subtract numbers from variables, so only subtract like-terms. 4x - 3x = 1x (or just 'x') 1 - (-4) = 5; Put our difference of terms together; 1x + 5;
