P = 2 * | t - 6 | + 4 = 8
( Remark : 8 mean 8 thousands )
2 * | t - 6 | = 8 - 4
2 * | t - 6 | = 4 Divide both sides with 2
| t - 6 | = 2
| t - 6 | = t - 6
and
| t - 6 | = - ( t - 6 ) also
You must solve two equations:
1.)
t - 6 = 2
t = 2 + 6
t = 8
and
2.)
- ( t - 6 ) = 2
- t + 6 = 2
- t = 2 - 6
- t = - 4 Multiply both sides with - 1
t = 4
So equation:
P = 2 * | t - 6 | + 4 = 8
has the two solutions :
t = 4 yrs
and
t= 8 yrs
Proof:
P = 2 * | t - 6 | + 4
for t = 4 yrs
P = 2 * | 4 - 6 | + 4 =
2 * | - 2 | + 4 =
2 * 2 + 4 =
4 + 4 = 8
P = 2 * | t - 6 | + 4
for t = 8 yrs
P = 2 * | 8 - 6 | + 4 =
2 * | 2 | + 4 =
2 * 2 + 4 =
4 + 4 = 8