Answer:
42
Step-by-step explanation:
f(-5) = -9 × (-5) - 3 = 45 - 3 = 42
If you have any questions about the way I solved it, don't hesitate to ask me in the comments below =)
Answer:
9 hours
Step-by-step explanation:
1 chapter ≈ .5 hour
18 x .5 = 9
Answer:
The answer would not be A. It is B
Step-by-step explanation:
Because you are subtracting the equations, on the right side of the equal sign, you are subtracting -5 from 7. This is 7-(-5), which is equal to 7+5=12, not -12.
Answer: his weekly allowance is $8
The model to solve the problem is
X/2+8=12
Step-by-step explanation:
To get Eduardo's weekly allowance
Say it is x
Now he spent half of x on clothes and earns extra $8 more to end up with $12
Therefore
x/2+8=12
x/2=12-8
x/2=4
x=8
Given Information:
Area of rectangle = 16 square feet
Required Information:
Least amount of material = ?
Answer:
x = 4 ft and y = 4 ft
Step-by-step explanation:
We know that a rectangle has area = xy and perimeter = 2x + 2y
We want to use least amount of material to design the sandbox which means we want to minimize the perimeter which can be done by taking the derivative of perimeter and then setting it equal to 0.
So we have
xy = 16
y = 16/x
p = 2x + 2y
put the value of y into the equation of perimeter
p = 2x + 2(16/x)
p = 2x + 32/x
Take derivative with respect to x
d/dt (2x + 32/x)
2 - 32/x²
set the derivative equal to zero to minimize the perimeter
2 - 32/x² = 0
32/x² = 2
x² = 32/2
x² = 16
x =
ft
put the value of x into equation xy = 16
(4)y = 16
y = 16/4
y = 4 ft
So the dimensions are x = 4 ft and y = 4 ft in order to use least amount of material.
Verification:
xy = 16
4*4 = 16
16 = 16 (satisfied)