9514 1404 393
Answer:
6x^2 +x -12
Step-by-step explanation:
Substitute for A and B and collect terms.
2B +3A
= 2(3x^2 -x +3) +3(x -6) . . . . substitute for A and B
= 6x^2 -2x +6 +3x -18 . . . . . eliminate parentheses
= 6x^2 +x -12 . . . . . . . . . . . . collect terms
I think the answer is y=-2(x-2)^2+6
Answer:
x = 10 cm, y = 5 cm gives a minimum area of 300 cm^2.
Step-by-step explanation:
V= x^2y = 500
Surface area A = x^2 + 4xy.
From the first equation y = 500/x^2
So substituting for y in the equation for the surface area:
A = x^2 + 4x * 500/x^2
A = x^2 + 2000/x
Finding the derivative:
dA/dx = 2x - 2000x^-2
dA/dx = 2x - 2000/x^2
This = 0 for a minimum/maximum value of A, so
2x - 2000/x^2 = 0
2x^3 - 2000 = 0
x^3 = 2000/ 2 = 1000
x = 10
Second derivative is 2 + 4000/x^3
when x = 10 this is positive so x = 10 gives a minimum value of A.
So y = 500/x^2
= 500/100
= 5.
Greetings from Brasil...
According to the statement of the question, we can assemble the following system of equation
X = 7 + 3Y i
X + Y = 75 ii
So, multiplying ii by -1 and adding with i
X = 7 + 3Y
- X - Y = - 75
- Y = 7 + 3Y - 75
4Y = 68
Y = 17
for X we will use ii:
X + Y = 75
X + 17 = 75
X = 58
The smaller number is: 17
