If x and y are negative integers and x – y = 1, what is the least possible value for xy?
1 answer:
X=y+1
Least possible value for y(y+1)? Well, it appears for y halfway between the roots (you know what a parabola is, don't you?). That y is -0.5, so let's calculate -0.5*0.5, which is -0.25.
The least possible value is
Well, not really :)) The two values must be both negative, so we can't take one of them to be 0.5! As we lower the values, however, the product grows, reaching 0 when x=0 and y=-1, and further increasing as x and y lower. Thus, we would actually take x=0 and y=-1.
Least possible value for y(y+1)? Well, it appears for y halfway between the roots (you know what a parabola is, don't you?). That y is -0.5, so let's calculate -0.5*0.5, which is -0.25.
The least possible value is
Well, not really :)) The two values must be both negative, so we can't take one of them to be 0.5! As we lower the values, however, the product grows, reaching 0 when x=0 and y=-1, and further increasing as x and y lower. Thus, we would actually take x=0 and y=-1.
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Given:
- There are two savings accounts - account A has $150 and account B has $300 to begin with.
- Malorie deposits $16 in account A and $12 in account B every month.
To Find:
The number of months where the balance of both is equal and the balance itself.
Solution:
In 37.5 months, the account balances in both accounts will be equal.
This balance will be equal to $750 in both account A and B.
Calculation:
Let x be the number of months where both the accounts have equal balance.
So, at the end of x months, 16x is the amount of money that will be added to account A (since $16 is added every month).
And the total amount at the end of x months will therefore be $(150+16x)
Similarly, at the end of x months, 12x is the amount of money that will be added to account B (since $12 will be added every month).
And the total amount at the end of x months will therefore be $(300+12x)
By our assumption, x is the number of months it will take for both the accont balances will be equal. Therefore, we have the equation
Therefore, in 37.5 months, the account balances in both accounts will be equal.
This balance will be equal to i.e. $750 will be the balance in both account A and B.