Answer:
Explanation:
This is segment addition in Geometry. Picture a straight line with endpoints A and C. B is a point stuck somewhere between them. The length of AC then is equal to the length of AB plus the length of BC. In algebraic terms:
AC = AB + BC. Filling in from the problem:
81 = 2x + 1 + 6x and combine like terms:
81 = 8x + 1 and subtract over the 1:
80 = 8x and divide by 8 to find
x = 10.