(7x+2)(20-3x/4) = 140x + 40 - 21x²/4 - 3x/2 = -21/4 x² + 138 1/2 x + 40
this is one of those multiplications that doesn't make the result look any simpler...
Answer:


And we are 95% confident that the true difference means are between 
Step-by-step explanation:
We know the following info:
sample mean for group 1
sample mean for group 2
sample standard deviation for group 1
sample standard deviation for group 2
sample size group 1
sample size group 2
We want to find a confidence interval for the difference of means and the correct formula to do this is:

Now we just need to find the critical value. The confidence level is 0.95 then the significance is
and
. The degrees of freedom are given by:

The critical value for this case would be :
And replacing into the confidence interval formula we got:


And we are 95% confident that the true difference means are between 
Answer:
D
Step-by-step explanation:
Answer:
662.433221
Step-by-step explanation:
907.07 × 1.09 × 0.67