Answer:
x is -5.
Step-by-step explanation:
*------------*------*
A B C
If point B is between A and C, then AB+BC=AC by segment addition postulate.
So we have the following equation to solve:
(x+17)+(x+13)=20
Distribute:
x+17+x+13=20
Reorder using commutative property:
2x+30=20
Subtract 30 on both sides (subtraction property):
2x=-10
Divide both sides by 2 (division property):
x=-5
So if x=-5, then
AB=x+17=-5+17=12
BC=x+13=-5+13=8
and AC=12+8=20.
