So first, you get the absolute value to one side:

Next, set up two equations; One where the value inside the absolute value lines is positive, and another where it is negative, and solve both for the variable:

Your answers are
8 and -8, or +-8.
Note that 1.485 is the same as 1485/1000, the ratio of two integers. Thus, 1.485 is rational.
9/24
28/24
If you need an explanation just ask
Answer: -200
<u>Step-by-step explanation:</u>
P(t) = 800t - t²
P(600) = 800(600) - (600)²
= 480,000 - 360,000
= 120,000
P(400) = 800(400) - (400)²
= 320,000 - 160,000
= 160,000

0.35 is the answer because
0.35 x 1 is 0.35