"For any three consecutive numbers": x,y,z:
x
y=x+1
z=x+2
"prove algebraically that the largest number and the smallest number are factors"
x*z=
"of the number that is one less than the square of the middle number"
=y²-1
x*z=y²-1
x*(x+2)=(x+1)²-1
x²+2x=x²+2x+1-1
x²+2x=x²+2x
both sides of the equation are the same, so the statement is correct
What’s the shape of it?
If it’s a rectangle 20
Bot something with more than 4 sides 100cm
<span>=<span>49</span></span><span>(Decimal: 0.444444)</span>
The <em><u>correct answer</u></em> is:
We can conclude that 68% of the scores were between 55 and 85; 95% of the scores were between 40 and 100; and 99.7% of the scores were between 25 and 100.
Explanation:
The empirical rule tells us that in a normal curve, 68% of data lie within 1 standard deviation of the mean; 95% of data lie within 2 standard deviations of the mean; and 99.7% of data lie within 3 standard deviations of the mean.
The mean is 70 and the standard deviation is 15. This means 1 standard deviation below the mean is 70-15 = 55 and one standard deviation above the mean is 70+15 = 85. 68% of data will fall between these two scores.
2 standard deviations below the mean is 70-15(2) = 40 and two standard deviations above the mean is 70+15(2) = 100. 95% of data will fall between these two scores.
3 standard deviations below the mean is 70-15(3) = 25 and three standard deviations above the mean is 70+15(3) = 115. However, a student cannot score above 100%; this means 99.7% of data fall between 25 and 100.
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