surface area (S) of a right rectangular solid is:
S = 2*L*W + 2*L*H + 2*W*H (equation 1)
where:
L = length
W = width
H = height
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you have:
L = 7
W = a
H = 4
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formula becomes:
S = 2*7*a + 2*7*4 + 2*a*4
simplify:
S = 14*a + 56 + 8*a
combine like terms:
S = 22*a + 56
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answer is:
S = 22*a + 56 (equation 2)
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to prove, substitute any value for a in equation 2:
let a = 15
S = 22*a + 56 (equation 2)
S = 22*15 + 56
S = 330 + 56
S = 386
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since a = 15, then W = 15 because W = a
go back to equation 1 and substitute 15 for W:
S = 2*L*W + 2*L*H + 2*W*H (equation 1)
where:
L = length
W = width
H = height
-----
you have:
L = 7
W = 15
H = 4
-----
equation 1 becomes:
S = 2*7*15 + 2*7*4 + 2*15*4
perform indicated operations:
S = 210 + 56 + 120
S = 386
-----
surface area is the same using both equations so:
equations are good.
formula for surface area of right rectangle in terms of a is:
S = 22*a + 56
-----
Answer:
B
Step-by-step explanation:
need a brainliest for this answer.. it took long to do.
The solution of the given expression will be (3d−3)(d+7)(d−9).
<h3>What is an expression?</h3>
Expression in maths is defined as the collection of the numbers variables and functions by using signs like addition, subtraction, multiplication, and division.
The solution of the given expression will be:-
E = (3d−3)(d+7)(d−9).
E = ( 3d² + 18d -21 ) ( d- 9 )
E = ( 3d³ + 18d² -21d - 27d² -162 +189 )
E = ( 3d³ + 9d² - 21d + 27 )
Therefore the solution of the given expression will be (3d−3)(d+7)(d−9).
To know more about Expression follow
brainly.com/question/723406
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