Answer:
5. x = -1
6. x = 2
Explanation:
5. AB = 5
BC = 2x + 6
AC = x + 10
AB + BC = AC (segment addition postulate)
5 + 2x + 6 = x + 10 (substitution)
Collect like terms
5 + 6 + 2x = x + 10
11 + 2x = x + 10
2x - x = - 11 + 10
x = -1
6. AB = 9x + 7
BC = -3x + 20
AC = 39
AB + BC = AC (segment addition postulate)
(9x + 7) + (-3x + 20) = 39 (substitution)
Solve for x
9x + 7 - 3x + 20 = 39
Collect like terms
9x - 3x + 7 + 20 = 39
6x + 27 = 39
Subtract 27 from both sides
6x + 27 - 27 = 39 - 27
6x = 12
Divided both sides by 6
6x/6 = 12/6
x = 2