To model half-life, use the formula

. Here,

is the amount remaining after a length of time

.

is the amount that you start with.

is the half-life. You plug in 50 for

, 10 for

, and 25 for

. You get

.
The answer to the question would be 455
X+4=2x+5
-1=x
hope this helps
Hello,
(10-4x²)-(7x+?)=3x-6x²
==>10-4x²-7x-3x+6x²=?
==>?=2x²-10x+10
Add the amount of choices, and divide by the number of customers surveyed.
40 + 32 + 8 + 20 = 100
40 customers were surveyed
100/40 = 2.5
The average number should be D) 2.5
hope this helps