19 x 3 = 57
57 - 9 = 48
Your answer is 19.
Answer: 
Step-by-step explanation:
All that is required here is to substitute x = 2x into the right side in the same way that is done for a numeric value.

Answer:
Population mean = 7 ± 2.306 × 
Step-by-step explanation:
Given - A university researcher wants to estimate the mean number
of novels that seniors read during their time in college. An exit
survey was conducted with a random sample of 9 seniors. The
sample mean was 7 novels with standard deviation 2.29 novels.
To find - Assuming that all conditions for conducting inference have
been met, which of the following is a 94.645% confidence
interval for the population mean number of novels read by
all seniors?
Proof -
Given that,
Mean ,x⁻ = 7
Standard deviation, s = 2.29
Size, n = 9
Now,
Degrees of freedom = df
= n - 1
= 9 - 1
= 8
⇒Degrees of freedom = 8
Now,
At 94.645% confidence level
α = 1 - 94.645%
=1 - 0.94645
=0.05355 ≈ 0.05
⇒α = 0.5
Now,

= 0.025
Then,
= 2.306
∴ we get
Population mean = x⁻ ±
×
= 7 ± 2.306 × 
⇒Population mean = 7 ± 2.306 × 
4:7 = 8:14
4 x 2 = 8. 7 x 2 = 14
If the triangle has the angle of 90°, 89° and 1° then 1 side length can be 3 in but all the side lengths cannot be 3 in.
<u>Explanation:</u>
The sum of all the angles of a triangle = 180°
So, if 1 angle is 90° and the 2nd angle is 89°, then the third angle will be 1°
and length of 1 side = 3 in
a = 3 in
Using the Sine rule,

On substituting the value:

Therefore, if the triangle has the angle of 90°, 89° and 1° then 1 side length can be 3 in and the triangle will be very acute but all the side lengths cannot be 3 in.