Answer: y = 31
Step-by-step explanation:
y = 3x + 10
y = 3(7) + 10               Plug in the 7 for x, because it shows x = 7 in the question. 
y = 21 + 10
y = 31
 
        
             
        
        
        
Answer:
Step-by-step explanation:
Distribute:
=9t+1+(7)(1)+(7)(9t)
=9t+1+7+63t
Combine Like Terms:
=9t+1+7+63t
=(9t+63t)+(1+7)
=72t+8
 
        
             
        
        
        
Answer:
8 and 10
Step-by-step explanation:
Set the first number as x, the second as y
x+y=18
2x-y=6
This is an binary system of first order equations
3x=24
x=8
y=10
 
        
             
        
        
        
Let X be the score on an english test which is normally distributed with mean of 31.5 and standard deviation of 7.3
μ = 31.5 and σ =7.3 
Here we have to find score that separates the top 59% from the bottom 41%
So basically we have to find here x value such that area above it is 59% and below it is 49%
This is same as finding z score such that probability below z score is 0.49 and above probability is 0.59
P(Z < z) = 0.49
Using excel function to find the z score for probability 0.49 we get
z = NORM.S.INV(0.49)
z = -0.025
It means for z score -0.025 area below it is 41% and above it is 59%
Now we will convert this z score into x value using given mean and standard deviation
x = (z* standard deviation) + mean
x = (-0.025 * 7.3) + 31.5
x = 31.6825 ~ 31.68
The score that separates the top 59% from the bottom 41% is 31.68 
 
        
             
        
        
        
Answer:
I think the second one is the answer ; 2√b