Answer:
y = (x-3)^2 - 17
Step-by-step explanation:
To complete the square, take the middle term bx and divide it in two. Then take the square.
x^2 - 6x - 8 has bx = -6x. Take -6/2 = -3. Square -3^2 = 9.
Now to finish completing the square add 9 and subtract 9 from one side.
y = x^2 - 6x - 8
y = (x^2 - 6x +9) -9 - 8
y = (x-3)^2 - 17
31 < -5x + 6
<u>-6 -6</u>
<u>25</u> < <u>-5x</u>
-5 -5
-5 < x
x > -5
Answer:
y< -1
Step-by-step explanation:
X/13
Quotient means divide. So you will make a fraction. On the top goes x and on the bottom is 13
Answer:
2 km/h
Step-by-step explanation:
Let x represent the speed of the river current, t₁ be the time spent rowing against the current and t₂ be the time spent rowing with the current.
Since the speed of the still water = 20 km/h.
The speed of rowing against the current = (20 - x)
The speed of rowing with the current = (20 + x)
We know that velocity = distance / time. Hence time = distance / velocity
t₁ = 36 / (20 - x)
t₂ = 22 / (20 + x)
but t₁ + t₂ = 3 hours
Therefore:
3 = 36 / (20 - x) + 22 / (20 + x)
multiply through by 400 - x²
3(400 - x²) = 36(20 + x) + 22(20 - x)
1200 - 3x² = 720 + 36x + 440 - 22x
3x² + 14x -40 = 0
This gives x = -6.7 or x = 2
x cannot be negative therefore x = 2 km/h
The speed of the river current is 2 km/h
