Answer:

Step-by-step explanation:
y′′ + 4y′ − 21y = 0
The auxiliary equation is given by
m² + 4m - 21 = 0
We solve this using the quadratic formula. So

So, the solution of the equation is

where m₁ = 3 and m₂ = -7.
So,

Also,

Since y(1) = 1 and y'(1) = 0, we substitute them into the equations above. So,


Substituting A into (1) above, we have

Substituting B into A, we have

Substituting A and B into y, we have

So the solution to the differential equation is

Answer:
They can buy up to 240 drinks.
Step-by-step explanation:
Let x = number of drinks
The price of 1 drink is 75¢ = $0.75
The price of x drinks is 0.75x
The store gives a discount of $100.
The rice of x drinks is
0.75x - 100
The total price of the drinks must be less than or equal to $80.
0.75x - 100 ≤ 80
Add 100 to both sides.
0.75x ≤ 180
Divide both sides by 0.75
x ≤ 240
Answer: They can buy up to 240 drinks.
The answer is
(2n-3)(n+3)
i hope this helps :)
Answer:
StartFraction p over 0.69 EndFraction
69p
Step-by-step explanation:
The distance between the tree and the tower is 30√3m.
Justification:
<u>Let the situation be in a right angleABC form as shown in attached figure</u>.
<u>Given the height of the tower is 30m and the angle of depression to the base of the tree measure 30°</u>.
So, In ΔABC
tanθ = p/b
tan30° = 30/BC
1/√3 = 30/BC
BC = 30√3m.