Answer:
D
Step-by-step explanation:
w = 6 m
L = 1/2 m
Area = 1/2 * 6
Area = 3 m^2
Are you sure you have the givens correct? If you are hesitant about this answer, ask your instructor how it is done.
Edit
In that case (L = 12) then the area is
Area = 12 * 6
Area = 72
So the answer is D
5x + 25y = 60....multiply by -3
3x + 15y = 42....multiply by 5
-------------------
-15x - 75y = - 180 (result of multiplying by -3)
15x + 75y = 210 (result of multiplying by 5)
-------------------add
0 = 30...incorrect.....this system has no solutions
Answer:
It will take the first person 12 days and the second person x+12 or 20 days
Step-by-step explanation:
The equation for time to do a job is
1/A + 1/B = 1/C
where A is the time for person A to do the job alone
B is the time for person B to do the job alone
and C is the time for A and B to do the job together
Person A does it in x days and Person B does it in x+8 days and together they do it in 7.5 days
Substituting in
1/ (x) + 1/ (x+8) = 1/ 7.5
Multiply by (x)(x+8)(7.5) to clear the fractions
(x)(x+8)(7.5)(1/ (x) + 1/ (x+8)) = (1/ 7.5)(x)(x+8)(7.5)
Distribute
(x)(x+8)(7.5)(1/ (x)) +(x)(x+8)(7.5)( 1/ (x+8)) = (1/ 7.5)(x)(x+8)(7.5)
Cancel
(x+8)(7.5) + 7.5x = (x)(x+8)
Distribute
7.5x +60 +7.5x = x^2 +8x
Combine like terms
15x +60 = x^2 +8x
Subtract 15x from each side
15x-15x +60 = x^2 +8x-15x
60 = x^2 -7x
Subtract 60 from each side
60-60 = x^2 -7x - 60
0 = x^2 -7x - 60
Factor
0 = (x-12) *(x+5)
Using the zero product property
x-12=0 x+5=0
x=12 x=-5
Since the number of days cannot be zero
It will take the first person 12 days and the second person x+12 or 20 days
Well first you would have to full get rid of that 7.
So, -2/3x+7-7=3-7 Which then equals -2/3x= -4
Then you would want to get x by it's self.
So, -2/3x x (-3/2)= -4 x (-3/2) Which then equals x= 6
So your answer is, x= 6