Answer:
66 °F
Step-by-step explanation:
At 4 P.M., the temperature had decreased by 3° from the temperature at 3 P.M., so was ...
4 P.M. temp = 78 °F -3° = 75 °F
This was repeated until 7 P.M.
5 P.M. temp = 75 °F -3° = 72 °F
6 P.M. temp = 72 °F -3° = 69 °F
7 P.M. temp = 69 °F -3° = 66 °F
The temperature at 7 P.M. was 66 °F.
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Of course the repeated subtraction can be simplified using multiplication. The subtraction of 3° four times is equivalent to the subtraction of . . .
(3°)(4) = 12°
That is, the temperature at 7 P.M. is ...
78 °F -3°×4 = 78 °F -12° = 66 °F
Answer:
a = 2, b = -9, c = 3
Step-by-step explanation:
Replacing x, y values of the points in the equation y = a*x^2 + b*x +c give the following:
(-1,14)
14 = a*(-1)^2 + b*(-1) + c
(2,-7)
-7 = a*2^2 + b*2 + c
(5, 8)
8 = a*5^2 + b*5 + c
Rearranging:
a - b + c = 14
4*a + 2*b + c = -7
25*a + 5*b + c = 8
This is a linear system of equations with 3 equations and 3 unknows. In matrix notation the system is A*x = b whith:
A =
1 -1 1
4 2 1
25 5 1
x =
a
b
c
b =
14
-7
8
Solving A*x = b gives x = Inv(A)*b, where Inv(A) is the inverse matrix of A. From calculation software (I used Excel) you get:
inv(A) =
0.055555556 -0.111111111 0.055555556
-0.388888889 0.444444444 -0.055555556
0.555555556 0.555555556 -0.111111111
inv(A)*b
2
-9
3
So, a = 2, b = -9, c = 3
Possible dimension of a box with a volume of 100 cubic cm
10 x 10 x 1 = 100
10 x 5 x 2 = 100
5 x 5 x 4 = 100
Surface area:
10 x 10 x 1 dimensions:
10 x 10 = 100 x 2 = 200 sq.cm
10 x 1 = 10 x 4 = 40 sq. cm
240 sq. cm * $0.05 / 100 sq.cm = $0.12 per box
0.12 per box * 100 boxes = $12
10 x 5 x 2 dimension
10 x 5 = 50 x 2 = 100 sq. cm
10 x 2 = 20 x 2 = 40 sq. cm
5 x 2 = 10 x 2 = 20 sq. cm
160 sq. cm * $0.05/100 sq. cm = $0. 08 per box
0.08 per box * 100 boxes = $8
5 x 5 x 4 dimension
5 x 5 = 25 x 2 = 50 sq. cm
5 x 4 = 20 x 4 = 80 sq. cm
130 sq. cm * $0.05/100 sq. cm = $0.065 per box
0.065 per box * 100 boxes = $6.50
The best dimension to use to have the least cost to make 100 boxes is 5 x 5 x 4. It only costs $6.50 to make 100 boxes.
Answer:
Arc JK: 27°
Arc NJ: 153°
Arc JL: 117°
My guess on arc KNM is 207°
My other guess for MJL is 297
JKM 180°
Step-by-step explanation:
Answer:
B(6 , -11)
Step-by-step explanation:
(x-2 , y+3) = (4 , -8)
Compare the x & y co ordinates
x - 2 = 4 ; y + 3 = -8
x = 4 +2 ; y = -8 - 3
x = 6 ; y = -11
B(6 , -11)
