The table shows the scores of 20 students on a history test. what is the average student score?
score. number of students
90. 3
85. 5
80. 3
75. 4
70. 2
60. 0
55. 3
a. 26
b. 74
c. 77
d. 85

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d

step-by-step explanation:

step-by-step explanation:

the answer is 128

let's call the solutions x₁ = (5 - 2√7)/3 and x₂ = (5 + 2√7)/3

then the equation is (x-x₁)(x-x₂) = 0

if you fill that in you get a lot of numbers which you can recognize as ax²+bx+c=0.

step-by-step explanation:

you can see that a=1 (there is just an x²)

b = (-5 -2√7 + 2√7 - 5)/3 = -10/3

c = -2√7)/3 ) * (-5+2√7)/3) = -1/3

so your answer is 3x^2 – 10x – 1 = 0