Answer:
-8
Step-by-step explanation:
-3x+7x-8=34+9x-2
we move the x's to the left and the numbers to the right
4x-9x=32+8
-5x=40
x=-40/5
x=-8
Y= x + 3
1. Find the gradient(slope)
1 - 7 / - 2 - 4
=1
2. Find the y. Intercept ( c )
Y = x + c
Replace by any of the two coordinates given (4 , 7 )
7 = 4 + c
C= 3
Equation => Y = x + 3
We cannot calculate the confidence interval without the sample size. However, for the second question, the sample size needed would be 49.
The formula we use is

To find the z-score:
Convert 98% to a decimal: 0.98
Subtract from 1: 1-0.98 = 0.02
Divide by 2: 0.02/2 = 0.01
Subtract from 1: 1-0.01 = 0.99
Using a z-table (http://www.z-table.com) we see that this value is closest to a z-score of 2.33.
Using the z-score, our standard deviation (9) and our margin of error (3), we have: