Find the value of a.
3a-9=15

Step-by-step explanation:

3a - 9= 15

To solve the equation send the constants to the right side of the equation

That's

3a = 15 + 9

simplify

3a = 24

Divide both sides by 3

The final answer is

a = 8

Hope this helps you

a = 8

Explanation:

Step One - Add nine to both sides of the equation. This is the first step is to isolate the variable, a. This step will remove the negative nine from the equation.

3a - 9 = 15

3a - 9 + 9 = 15 + 9

3a = 24

Step 2 - Divide both sides of the equation by three. This is the last step to isolate the variable, a.

3a = 24

3a/3 = 24/3

a = 8

Since we have fully isolated the variable, a, we have determined its value.

Therefore, in the equation 3a - 9 = 15 the value of the variable is a = 8.

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: