Given:
The expression is
.
To find:
The position of parentheses inserted in the expression to get the value 19
Step-by-step explanation:
We have,

Now,




There are more ways to apply the parenthesis, but we do not get 19.



And many more possibilities.
Therefore, the expression after inserting the parentheses is
.
Answer:
Nicholas bought 1.8 lbs, and Jane bought 3lbs.
Step-by-step explanation:
Divide the total amount by how much it is per pound, so 8.10 divided by 4.50 = 1.8 and 9.75 divided by 3.25= 3
Using an exponential function, it is found that it takes 18.6 days for 80% of the material to decay.
The amount of a substance after t days is modeled by:

In which:
- k is the decay rate, as a decimal.
- A(0) is the initial amount.
The half-life is of 8 days, hence
, and this is used to find k.







Hence:

The time it takes for 80% of the material to decay it t for which
, hence:






It takes 18.6 days for 80% of the material to decay.
To learn more about exponential functions, you can take a look at brainly.com/question/24906920
Answer:
x = 8
Step-by-step explanation:
Step 1 : Simplify the equation
3(x-5) + 7x = 65
3x - 15 + 7x = 65
Step 2 : Make x the subject
3x + 7x = 65 + 15
10x = 80
x = 80/10
x = 8
!!