28.50x + 110.99(14-x)=811.45
distribute
28.50 x + 1553.86-110.99x =811.45
combine like terms
-82.49x+1553.86=811.45
subtract 1553.86 from each side
-82.49x =-742.41
divide by -82.49
x=9
He bought 9 of the 28.50 features and 5 of the 110.99 features
-1 use mathpapa it will give you the answar

÷

is the equation
When dividing fractions, you "flip-flop" and multiply
So what that means is that you flip the second fraction and multiply
So

is now

Now the equation is

×

which equals

Your answer is
Answer:
5r^3 + 4r^2 - 8r + 16
Step-by-step explanation:
(8 + 5r^3 - 2r^2) - (8r - 8 - 6r^2) =
The first set of parentheses is there just to show you that what is inside is a polynomial. The second set of parentheses has a second polynomial inside. The subtraction sign just to the left of the second set of parentheses shows that you are subtracting the second polynomial from the first one.
The first set of parentheses is not needed and can be dropped.
You are subtracting the second polynomial fromt he first one, so you can think of the the subtraction sign as a -1, and you need to distribute the -1 by the second polynomial, That will result in all signs inside the second set of parentheses changing.
Below, just the first set of parentheses is removed.
= 8 + 5r^3 - 2r^2 - (8r - 8 - 6r^2)
Now, we change every sign inside the second set of parentheses by distributing -1.
= 8 + 5r^3 - 2r^2 - 8r + 8 + 6r^2
Now we need to combine like terms. Like terms have the same variable part. We can rearrange the terms grouping like terms together before combining them. Also, it is customary to list the terms in descending order of degree.
= 5r^3 - 2r^2 + 6r^2 - 8r + 8 + 8
Now we combine like terms.
= 5r^3 + 4r^2 - 8r + 16
One of the approaches:
Each couple can send only one "representative" to the committee. Let's see in how many ways we can choose 3 couples (as there should be 3 members) out of 4 to send only one "representatives" to the committee: 4C3=4.
But each of these 3 couples can send two persons (husband or wife): 2*2*2=2^3=8.
Total # of ways: 4C3*2^3=32.
hope it helped a bit