Step-by-step explanation:
Let x be the number of logs=18 hours
6 logs=4 hours
X*4=18*6
4x=108
x=27 logs
so therefore 27 logs are needed to keep the fire burning for 18 hours
 
        
                    
             
        
        
        
Answer: 49x^2=-21x-2 quadratic functions -1/7and -2/7    
Step-by-step explanation:
Quadratic function:
In elementary algebra, the quadratic formula is a formula that provides the solution to a quadratic equation. There are other ways of solving a quadratic equation instead of using the quadratic formula, such as factoring, completing the square, graphing and others. 
Move terms to the left side
49 =-21x-2
  =-21x-2
49 -(-21x-2) =0
  -(-21x-2) =0
  Distribute
49 -(-21x-2) =0
  -(-21x-2) =0
49 +21x+2=0
+21x+2=0
Use the quadratic formula
  x=(-b±√ -4ac  ) / 2a
  -4ac  ) / 2a
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
Once in standard form, identify a, b, and c from the original equation and plug them into the quadratic formula.
  49 +21x+2=0
+21x+2=0
let, a=49
b=21
c=2
  Replace with values in this equation
X=(-b±√ -4ac  ) / 2a
  -4ac  ) / 2a
Simplify
Evaluate the exponent
Multiply the numbers
Subtract the numbers
Evaluate the square root
Multiply the numbers
x=(-21±7) /98
Separate the equations
To solve for the unknown variable, separate into two equations: one with a plus and the other with a minus.Separate
x=(-21+7) /98
x=(-21-7) /98
Solve
Rearrange and isolate the variable to find each solution
x=-1/7
x=-2/7
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    Learn more about area here https://brainly.in/question/5597925
#SPJ9
                  
    
    
                                                                                                                                                                                                    
 
        
             
        
        
        
Answer:  three sets of value show 3 consecutive increases and they could be the intensities during fourth, fifth, and six visits:
- 66%, 69%, 72%; 
- 63%, 65%, 67%, and 
- 67%, 72%, 77%
Explanation: 
1) The program recommends a constant intensity for 3 visits, which is what the table shows:
Day        Intensisty
1             63%
2            equal ⇒ 63%
3            equal ⇒ 63%
2) Hence, you have to determine the valid sets that meet the recommendation for the fourth, fifth, and six visits, which are the next three.
2) For the next three visits, the program recommensd increasing intensities. 
There are three options that show 3 consecutive increases; they are:
- 66%, 69%, 72%; 
- 63%, 65%, 67%, and 
- 67%, 72%, 77%
Therefore, those are the choices that apply.
 
        
             
        
        
        
Answer:
There is a 25/81 probability that Grace will make both of her next two shots.
Step-by-step explanation:
The probability of her making the first shot is 5/9.
The probability of her also making the shot after that is still 5/9, that does not change.
To find the probability of both of those events, multiply the fractions.
5/9 * 5/9
25/81.