Answer:
x=-2
y=9
Step-by-step explanation:
3=y+3x ---- A
-x+3y=29 ----B
step 1. rearrange equation A, so you have the "y" variable on one side
3=y+3x
-3x -3x
3-3x=y
y=3-3x ---- C
step 2. Substitute equation C into equation B in place of "y"
-x+3(3-3x)=29 ---foil
-x+9-9x=29 -- collect like terms
-10x+9=29
-9 -9
-10x=20
÷-10 ÷-10
x=-2
Step 3. Substitute x=-2 into equation C to find y
y=3-3(-2)
y=3+6
y=9
Check you answer by subsituting x=-2 and y=9 back into equation A and B
Answer:
3/2
Step-by-step explanation:
1/12 + 1/6x = 3/4...multiply everything by common denominator of 12
1 + 2x = 9
2x = 9 - 1
2x = 8
x = 8/2
x = 4 <== he can play 4 rounds
Answer:
- Base Length of 84cm
- Height of 42 cm.
Step-by-step explanation:
Given a box with a square base and an open top which must have a volume of 296352 cubic centimetre. We want to minimize the amount of material used.
Step 1:
Let the side length of the base =x
Let the height of the box =h
Since the box has a square base
Volume, 

Surface Area of the box = Base Area + Area of 4 sides

Step 2: Find the derivative of A(x)

Step 3: Set A'(x)=0 and solve for x
![A'(x)=\dfrac{2x^3-1185408}{x^2}=0\\2x^3-1185408=0\\2x^3=1185408\\$Divide both sides by 2\\x^3=592704\\$Take the cube root of both sides\\x=\sqrt[3]{592704}\\x=84](https://tex.z-dn.net/?f=A%27%28x%29%3D%5Cdfrac%7B2x%5E3-1185408%7D%7Bx%5E2%7D%3D0%5C%5C2x%5E3-1185408%3D0%5C%5C2x%5E3%3D1185408%5C%5C%24Divide%20both%20sides%20by%202%5C%5Cx%5E3%3D592704%5C%5C%24Take%20the%20cube%20root%20of%20both%20sides%5C%5Cx%3D%5Csqrt%5B3%5D%7B592704%7D%5C%5Cx%3D84)
Step 4: Verify that x=84 is a minimum value
We use the second derivative test

Since the second derivative is positive at x=84, then it is a minimum point.
Recall:

Therefore, the dimensions that minimizes the box surface area are:
- Base Length of 84cm
- Height of 42 cm.
Answer:
D
Step-by-step explanation:
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