The distribution of scores on a recent test closely followed a Normal distribution with a mean of 22 points and a standard deviation of 4 points.
A What proportion of the students scored at least 25 points on this test?
B. What is the 31st percentile of the distribution of test scores.
C. The teacher wants to transform the test scores so that they have an
approximately Normal distribution with a mean of 80 points and a standard
deviation of 10 points. To do this, she will use a formula of the form:
new score = a +b(old score) . Find the values of a and b that the teacher
should use to transform the distribution of test scores.
D. Before the test, the teacher gave a review assignment for homework. The
maximum score on the assignment was 10 points. The distribution of scores on
this assignment had a mean of 9.2 and a standard deviation of 2.1 points. Would
it be appropriate to use a Normal distribution to calculate the proportion of
students who scored below 7 points on this assignment? Explain.

Pl help!!

5x+40

5(x + 8)

7x - 49

7(x - 7)

18x + 9

9(2x + 1)

15x - 10

5(3x - 2)

step-by-step explanation:

for number one all you have to do is factor 5 out of 5x + 40

for number 2 factor 7 out of 7x - 49

for number three factor 9 out of 18x + 9

for number four factor 5 out of 15x - 10

$119.20

step-by-step explanation:

$372.50 - 60% off is $149. $149-20% off is $119.20

1. when "a" is a root of a polynomial, (x -a) is a factor of it. for the three roots given, the factors of the desired polynomial are (x +2)(x -1/2)(x -3).

in order to make the leading coefficient be negative, we need to multiply this product by a negative number. any negative number will do, but we choose a small (magnitude) value that will eliminate the fraction: -2.

then

f(x) = -2(x +2)(x -1/2)(x -3) = -(x +2)(2x -1)(x -3)

= -(2x² +3x -2)(x -3)

= -(2x³ -3x² -11x +6)

f(x) = -2x³ +3x² +11x -6

2. a graph created by the desmos on-line graphing calculator is shown, and the zeros are highlighted.

3. as indicated in part 1, the multiplier of this equation can be anything and the zeros will remain the same. you want a negative leading coefficient, so the "anything" is restricted to any of the infinite number of numbers that will make that be the case.