Answer: D) 
Step-by-step explanation:
As per given , we have
Sample size : n= 15
sample mean : 
Sample standard deviation: s= $20
Since population standard deviation is unknown , so we use t-test.
Significance level for 95% confidence : 
Critical t-value : 
[Using students' t-value table]
Required 95% Confidence interval :-
Hence, the required 95% confidence interval for the mean amount its credit card customers spent on their first visit to the chain's new store in the mall assuming that the amount spent follows a normal distribution.:
Answer:26
Step-by-step explanation:
Y=1.25^x-2/5-10
Take log of both sides
So Y+10=1.25^x-2/5
So log to base 10 of the two sides of the equation is
Log(Y+10)=X-2/5log1.25.
To make X the subject, divide both sides by log1.25.
Log(Y+10)/log1.25=X-2/5.
Recall that Y was given to be 115
It becomes log(115 +10)/Log1.25=x-0.4
21.64=x-0.4
X=25.6
It’s 29b disinfect r Fido’s w. R fndjdjdis
<h3>
Answer:</h3>
42. 29°
43. 3x³ +2x² -3x +10
44. 20a² +68a
<h3>
Step-by-step explanation:</h3>
42. The right-angle corner tells you the two marked angles are complementary — they sum to 90°.
(-3x +20)° + (-2x +55)° = 90°
-5x +75 = 90 . . . . . . . . . . collect terms, divide by °
-5x = 15 . . . . . . . . . . . . . . . subtract 75
x = -3 . . . . . divide by the coefficient of x
The angle of interest is (-3x+20)°. Filling in the found value for x, we have ...
(-3·(-3) +20)° = 29° = m∠BDC
___
43. The distributive property is useful for multiplying polynomials.
(x +2)(3x² -4x +5) = x(3x² -4x +5) +2(3x² -4x +5)
= 3x³ -4x² +5x +6x² -8x +10 . . . . . eliminate parentheses
= 3x³ +2x² -3x +10
___
44. Area is the product of length and width, so this becomes a problem in multiplying polynomials.
area = (5a +17)(4a) = 20a² +68a . . . . area in square feet
<span><span>(<span>sinx</span>−<span>tanx</span>)</span><span>(<span>cosx</span>−<span>cotx</span>)</span></span>
<span>=<span>(<span>sinx</span>−<span><span>sinx</span><span>cosx</span></span>)</span><span>(<span>cosx</span>−<span><span>cosx</span><span>sinx</span></span>)</span></span>
<span>=<span>sinx</span><span>(1−<span>1<span>cosx</span></span>)</span><span>cosx</span><span>(1−<span>1<span>sinx</span></span>)</span></span>
<span>=<span>sinx</span><span>(<span><span>cosx</span><span>cosx</span></span>−<span>1<span>cosx</span></span>)</span><span>cosx</span><span>(<span><span>sinx</span><span>sinx</span></span>−<span>1<span>sinx</span></span>)</span></span>
<span>=<span><span>sinx</span><span>cosx</span></span><span>(<span>cosx</span>−1)</span><span><span>cosx</span><span>sinx</span></span><span>(<span>sinx</span>−1)</span></span>
<span>=<span>(<span>cosx</span>−1)</span><span>(<span>sinx</span>−1<span>)</span></span></span>
