The question is
in the link below

D: -3

Step-by-step explanation:

In order to find a slope of a line from two pairs, one way you can do that is by using a formula.

The formula is as follows:

Y² - Y¹

⁻⁻⁻⁻⁻⁻⁻⁻⁻

X² - X¹

Using this formula, let's plug in our values.

1. Our first Y, is -4. Place that into the equation above for Y².

2. Our second Y, is 8. Place that into Y¹. Wait! Since it's negative in the equation, your positive eight must turn into a -8.

3. Our first X, is 3. Just like our first Y, plug it into your X².

4. Our second X, is -1. Since it is already negative, and the equation is has a negative in it, the negative plus a negative makes the number positive.

Your equation should look like this: (now solve)

-4 - 8           -12

=  

3 + 1            4

Great, you've made it this far, there's ONE more step! Simplify the problem!

4 goes into 12, 3 times! This is because 4x3 is 12! Since your 12 is negative, your answer MUST stay negative, leaving your answer as -3.

If this leaves you confused, feel free to ask me more questions! :)

step-by-step explanation: a reaction is first order. if the initial reactant concentration is 0.0200 m, and 25.0 days later the concentration is 6.25 x 10-4 m, then its half-life is:

207/8 is the right