The expression (−81)(−9) will give the value of 729.
<u>Step-by-step explanation:</u>
The given expression is (−81)(−9)
.
The both numbers in the expression are negative numbers and they are given inside the brackets.
This means that, the negative numbers must be multiplied to get a final value.
<u>The rules in multiplication are :</u>
- Positive number × Positive number = positive number
- Negative number × Positive number = negative number
- Positive number × Negative number = negative number
- Negative number × Negative number = positive number
From the rules, it can be determined that the result of any two negative numbers will be a positive number.
So, eliminate option A) and B) because they have negative sign.
The expression (−81)(−9) = -81 × -9
⇒ 729.
Therefore, the option C) and D) are not in match with 729. None of the options are not the value of the given expression (−81)(−9).
Answer:
you can buy 3 pineapples
Step-by-step explanation:
$4(3)= $12 total
Answer:
d
Step-by-step explanation:
Try using simple numbers like 1 as x and then try with the different functions until it works
This problem can be solved by the chicken rabbits method or you can just do simple algebra.
I.) Chicken and rabbits method
First assume all 110 coins are dimes and none are quarters.
We will have a total value of 11 dollars
Now for each dime we switch out for a quarter, we adds 15 cents to the total value.
18.50-11=7.50 dollars
There are 750/15=50 group of 15 cents in the 7 dollars and 50 cents.
This also meant that we need to switch out 50 dimes for 50 quarters.
So we have 50 quarters.
That first method is very good and very quick once you get the hang of it, now I'm going to show you the algebraic way to solve this.
Let's say there are x dimes and y quarters.
Set up equation
x+y=110
10x+25y=1850
Now solve multiply first equation by 10
10x+10y=1100
subtract
15y=750
y=50
Now we set the numbers of quarters to y so the answer is 50 quarters.
I personally recommend using algebra whenever you can because the practice is very important and you will eventually get really fast at setting up and solving equations. The first method is faster in this case but the second is more generalize, hope it helps.
