Answer:
a = -2
b = 1
c = 5
Step-by-step explanation:
Given:
2a + 4b + c = 5 ............(1)
a - 4b = - 6
or
a = 4b - 6 .............(2)
2b + c = 7
or
c = 7 - 2b ...........(3)
substituting 2 and 3 in 1, we get
2(4b - 6 ) + 4b + (7 - 2b) = 5
or
8b - 12 + 4b + 7 - 2b = 5
or
10b - 5 = 5
or
b = 1
substituting b in 2, we get
a = 4(1) - 6
or
a = -2
substituting b in 3, we get
c = 7 - 2(1)
or
c = 5
thus,
a = -2
b = 1
c = 5
Answer:
For least material to be used lengths of square base and sides = 10 units.
Step-by-step explanation:
Let the lengths of the square base and the sides = x feet, x feet and y feet
Area of the square base = x² feet
Volume of the rectangular prism = Area of the square base × Height
= x²y cubic feet
1000 = x²y
y =
-------(1)
Material used in the prism = Surface area of the rectangular prism
= 2(lb + bh + hl)
Here, h = height of the prism
l = length of the base
w = Width of the base
Material to be used (S) = 2(xy + x² + xy) - Area of lid
S = 2(x² + 2xy) - x²
S = x² + 2xy
Now by substituting the value of y from equation (1),
S = x² + 
= x² + 
For least amount of material used,
We will find the derivative of the given function and equate it to zero.
S' = 2x - 
2x -
= 0
2x³ = 2000
x³ = 1000
x = 10 feet
From equation (1),
y = 
y = 10 feet
Therefore, for least amount of the material used lengths of square base and sides will be 10 feet.
LWH-LWH
=12*20*5-4*2*0.5
=1200-32
=1168 cubic cms
Answer:
15.8 mi
Step-by-step explanation:
If I'm not mistaking parallel lines never touch