Answer:
x=8
Step-by-step explanation:
Answer:
26
Step-by-step explanation:
12-8=4
3(4)=12
12/2=6
6*5=30
30-4
26
Answer:
y = -2
Step-by-step explanation:
Put x as -19 and solve for y.
2(-19) - 5y = -28
Multiply.
-38 - 5y = -28
Add 38 on both sides of the equation.
-5y = -28 + 38
-5y = 10
Divide both sides by -5.
y = 10/-5
y = -2
If x represents the width of the poster (including borders), the area of the finished poster can be written as
.. a = x*(390/(x -10) +8)
.. = 8x +390 +3900/(x -10)
Then the derivative with respect to x is
.. da/dx = 8 -3900/(x -10)^2
This is zero at the minimum area, where
.. x = √(3900/8) +10 ≈ 32.08 . . . . cm
The height is then
.. 390/(x -10) +8 = 8 +2√78 ≈ 25.66 . . . . cm
The poster with the smallest area is 32.08 cm wide by 25.66 cm tall.
_____
In these "border" problems, the smallest area will have the same overall dimension ratio that the borders have. Here, the poster is 10/8 = 1.25 times as wide as it is high.
Answer:
The number of protons is the answer
