6. (6 pts) The batteries used by a calculator have useful lives that follow a normal distribution, with a mean of 1000 hours and a standard deviation of 200 hours. (a) Find the range of middle 95% batteries useful life. (b) A random sample of 100 batteries is drawn. Find the range of middle 95% sample means of batteries useful life.

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".

the workers who do no drive has no reasonable reason to buy gasoline due to they don't have anything to use it for

80

step-by-step explanation: