2x+40=60
2x=20
x=10
Answer:10
Let
and
. By the product rule,

By the power rule, we have
and
, but
are functions of
, so we also need to apply the chain rule:


and we have


So we end up with

Replace
to get everything in terms of
:

We can simplify this by factoring:


Answer:
112 km/h
125 km/hr
Step-by-step explanation:
Distance = time * speed
Distance = distance train 1 + distance train 2
474 = 2(s) + 2(s + 13)
Distribute
474 = 2s + 2s + 26
Combine like terms
474 = 4s + 26
Subtract 26 from both sides
448 = 4s
Divide both sides by 4
112 = s
s = 112 km/h
s + 13 = 125 km/hr