AC is 4 because of the side angle side postulate
X - y = 7
y = x - 7....the slope here is 1. A parallel line will have the same slope.
y = mx + b
slope(m) = 1
(1,0)...x = 1 and y = 0
now we sub and solve for b, the y int
0 = 1(1) + b
0 = 1 + b
-1 = b
so ur parallel line is : y = x - 1
Using the graphing you graph the two equations and then find the point where the two lines of the equation meet.
Hope this helps :)
1 + 2^1 = 3
3 + 2^2 = 7
7 + 2^3 = 15
15 + 2^4 = 31
31 + 2^5 = 63
63 + 2^6 = 127
so the next two terms in the sequence 1, 3, 7, 15, 31, is 63 and 127.
