#1)
Answer:
x=1 and y=12
Explanation:
y=5x+7
y=2x+10
This system should use substitution because the value of y is given in terms if x.
Substitution:
5x+7=2x+10
Solve:
3x=3
x=1
Substitute x to solve for y by plugging x into one if the original equations(doesn’t matter which one is used).
y=5x+7
y=5(1)+7
y=5+7
y=12
#2)
Answer:
x=-8 and y=2
Explanation:
y=2x+18
9y=-2x+2
This system also uses substitution. The value of y us already given in terms if c in the first equations, so we will substitute in the second equation.
Substitute:
9(2x+18)=-2x+2
Solve:
18x+162=-2x+2
20x=-160
x=-8
Now that we have the value if x, plug it into one of the original equations(doesn’t matter which equation) and substitute to find y.
y=2x+18
Substitute:
y=2(-8)+18
Solve:
y=-16+18
y=2
Answer:
The cooking club sales covers the expenditure when 2 piece of cakes are sold.
Step-by-step explanation:
Given:
Selling price of each piece of cake = $10
Cost for booth at fair = $10
Ingredients for each piece of cake = $5
We need to find the number of pieces of cake sold when the sales cover the expenditures.
Solution:
Let the number of pieces be 'x'
So We can say that the point at which the sales cover the expenditures can be calculated as Selling price of each piece of cake multiplied by number of pieces will be equal to Cost for booth at fair plus Ingredients for each piece of cake multiplied number of piece of cakes.
framing in equation form we get;
Now Subtracting both side by '5x' using Subtraction property we get;
Now Dividing both side by 5 we get;
Hence The cooking club sales covers the expenditure when 2 piece of cakes are sold.
From calculus, to determine the maxima or minima of the graph, get the derivative of the equation and equate to zero. So, we derive first the equation of the graph and equate to zero.
C = 0.25x² - 80x + 30000
dC/dx = 0 = 0.5x - 80 + 0
0.5x = 80
x = 80/0.5
x = 160 units
The minimum cost (although not asked) is:
C = 0.25(160)² - 80(160) + 30000
C = $23,600
The answer is 160 units.
