7x+5y is the answer
yepyep
        
             
        
        
        
<span>2r ≤ 3(2r - 7)
</span><span>2r ≤ 6r - 21
</span><span>21 ≤ 6r - 2r
</span><span>21 ≤ 4r
</span><span>21/4 ≤ r
r</span>

 21/4
r 

 5.25
 
        
        
        
Answer:
Number of Possible Sequence = 5 x 4 x 3 x 2 x 1 = 120 ways
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Answer: 135 days
Step-by-step explanation:
Since the amount of time it takes her to arrive is normally distributed, then according to the central limit theorem, 
z = (x - µ)/σ
Where
x = sample mean 
µ = population mean 
σ = standard deviation
From the information given,
µ = 21 minutes
σ = 3.5 minutes
the probability that her commute would be between 19 and 26 minutes is expressed as 
P(19 ≤ x ≤ 26) 
For (19 ≤ x),
z = (19 - 21)/3.5 = - 0.57
Looking at the normal distribution table, the probability corresponding to the z score is 0.28
For (x ≤ 26),
z = (26 - 21)/3.5 = 1.43
Looking at the normal distribution table, the probability corresponding to the z score is 0.92
Therefore,
P(19 ≤ x ≤ 26) = 0.92 - 28 = 0.64
The number of times that her commute would be between 19 and 26 minutes is 
0.64 × 211 = 135 days
 
        
             
        
        
        
Answer:
Step-by-step explanation:
Given equation is representing the graph of parabola which opens down and its pick is its vertex
<u>The vertex is calculated by vertex formula:</u>
- x = -b/2a for the equation y = ax² + bx + c
<u>In our case t is the vertex and its value is:</u>
- t = -42/(-1.5*2) = 42/3 = 14 seconds