By definition, the half life is a quantity is the time it takes to lose half of that quantity.
So, if the half life is 60 days, it means that after 60 days you have lost half the initial amount, i.e. you're left with 100 grams.
After another 60 days, you've lost, again, half of that amount, so you're left with 50 grams.
In other words, every time a half life period passes, you're left with half the quantity you had at the beginning of that period.
So, after two half-life periods (i.e. 120 days), you'll have half of the half of the initial quantity, i.e. one quarter.
Answer:
- Plan: separate the variable term from the constant term; divide by the coefficient of the variable.
- Steps: add 4 to both sides; collect terms; divide both sides by 3.
Step-by-step explanation:
The first step is to look a the equation to see where the variable is in relation to the equal sign, and whether there are any constants on that same side of the equal sign.
Here, the variable terms are on the left, and there is a constant there, as well. The plan for solving the equation is to eliminate the constant that is on the same side of the equation as the variable, then divide by the coefficient of the variable. To find that coefficient, we need to collect terms. In summary, the plan is to ...
- add 4 to both sides of the equation
- collect terms
- divide by the coefficient of the variable (3)
Executing that plan, the steps are ...
-2x -4 +5x +4 = 8 +4 . . . . add 4
3x = 12 . . . . . . . . . . . . . . . collect terms
x = 4 . . . . . . . . . divide by 3
Its 12y - 9 because when u add twelve pluus 12 it 24 then -21 is to 3 which 12 - 9 is 3
Is this multiple choice? I know that a is correct.
(x + 9)(x + 12) = 0
Expanding the brackets, we get:
