<span>Let x = represent the number of weeks of deposits
A = 120 + 5x the account balance after x weeks
The account balance is directly proportional to the number of weeks of deposits if:
A/x = constant
(120 + 5x)/x = 120/x + 5 is not a constant
For example:
After 1 week there will be: 120 + 1*5 = $125 on the account
After 2 week there will be: 120 + 2*5 = $130 on the account
After 3 week there will be: 120 + 3*5 = $135 on the account
But 125/1 <> 130/2 <> 135/3
The account balance is not proportional to the number of weeks of deposits.</span>
Answer:
1 6 15 20 15 6 1
Step-by-step explanation:
To figure this out, we need to look at Pascal's Triangle, which is a tricky little way to find the coefficients for any binomial expression like this! Check the attached photo.
Because this is to the sixth, we need the 6th row, which is <u>1 6 15 20 15 6 1.</u> From this, we know that those numbers are the coefficients!
Consider the equation y = x^2. No matter what x happens to be, the result y will never be negative even if x is negative. Example: x = -3 leads to y = x^2 = (-3)^2 = 9 which is positive.
Since y is never negative, this means the inverse x = sqrt(y) has the right hand side never be negative. The entire curve of sqrt(x) is above the x axis except for the x intercept of course. Put another way, we cannot plug in a negative input into the square root function for this reason. This similar idea applies to any even index such as fourth roots or sixth roots.
Meanwhile, odd roots such as a cube root has its range extend from negative infinity to positive infinity. Why? Because y = x^3 can have a negative output. Going back to x = -3 we get y = x^3 = (-3)^3 = -27. So we can plug a negative value into the cube root to get some negative output. We can get any output we want, negative or positive. So the range of any radical with an odd index is effectively the set of all real numbers. Visually this produces graphs that have parts on both sides of the x axis.
