Answer:
40 km on the highway
30 km on the city roads
Step-by-step explanation:
Let x = highway
Let y = city road
The time formula: time = distance / speed.
1) Since we do not know the distance travelled on the highway and city roads but we do know the total time taken, we can say x + y = 70. Set the distances x and y and all equated to 2 hours, since we do not know them, nor do we know the time. This is called a system of equations.
x + y = 70
x/80 + y/20 = 2
2) Solve the system of equations using substitution.
x = 70 - y
---------------
70 - y/80 + y/20 = 2
70 + 3y/80 = 2
y = 30
---------------------------------
x + 30 = 70
x = 70 - 30
x = 40
Therefore, the delivery truck travelled 40 km on the highway and 30 km on the city roads.
Answer:
In ΔABC
AB
2
=AC
2
+BC
2
⇒BC
2
=x
2
=17
2
−8
2
⇒x=15m.
Step-by-step explanation:
Differentiate
y = (r² – 9r) · eʳ
with respect to r.
As y is a product of two functions, then use the product rule:
dy d
—— = —— [ (r² – 9r) · eʳ ]
dr dr
dy d d
—— = —— (r² – 9r) · eʳ + (r² – 9r) · —— (eʳ)
dr dr dr
• The derivative of r² – 9r is 2r – 9;
• The derivative of eʳ is eʳ.
Therefore,
dy
—— = (2r – 9) · eʳ + (r² – 9r) · eʳ
dr
dy
—— = [ (2r – 9) + (r² – 9r) ] · eʳ
dr
dy
—— = (r² – 7r – 9) · eʳ <——— this is the answer.
dr
I hope this helps. =)
I would say this. 624 is rounded to 600, so you would take 600 divided by 6.
23,999 + 1
12,000 + 12,000
12,000 x 2
600 x 4
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