I think the answer should be 12.
This is the concept of algebra, to calculate the proportion of wool in each item we proceed as follows;
Let the amount of wool used for hat be x
amount of wool in sweater will be 5x
the amount of wool used in scarf will be x-5
therefore the total amount of wool will be:
x+5x+(x-5)=550
x+5x+x-5=550
7x-5=550
7x=550+5
7x=555
hence;
x=555/7
x=79
the amount used in hat x=79g
amount used in sweater 5x=395g
amount used in scarf=79-5=74g
When you match the pattern of (x+y)⁴ to (a+b)ⁿ, you see that a=x, n=4. Then the first term aⁿ can be found by substituting these values for "a" and "n":
... x⁴
Answer:

Step-by-step explanation:
We are given:

![interval = [a,b] = [0,2]](https://tex.z-dn.net/?f=interval%20%3D%20%5Ba%2Cb%5D%20%3D%20%5B0%2C2%5D)
Since
⇒ 
Riemann sum is area under the function given. And it is asked to find Riemann sum for the left endpoint.

Note:
If it will be asked to find right endpoint too,

The average of left and right endpoint Riemann sums will give approximate result of the area under
and it can be compared with the result of integral of the same function in the interval given.
So, 

Result are close but not same, since one is approximate and one is exact; however, by increasing sample rates (subintervals), closer result to the exact value can be found.