Answer:
The train ride is 3.5 hours
Step-by-step explanation:
We know that distance is equal to rate times time
d = rt
We know the distance and the rate
420 = 120*t
Divide each side by 120
420/120 = 120t/120
3.5 =t
The train ride is 3.5 hours
B, C, E, F
<h2>
Explanation:</h2>
In this problem, we have the following equation of a line written in Standard form:

So we need to choose the equations that has the same solutions as this equation. If we multiply each equation by a constant term and find the same solution as the given equation, then they will have the same solution. This is only true fro options B, C, E and F.
Option B.

So we get the same given equation. This option is valid!
Option D.

So we get the same given equation. This option is valid!
Option E.

So we get the same given equation. This option is valid!
Option F.

So we get the same given equation. This option is valid!
For the other options, there is no any constant term that multiplies both sides of the equation and gives us the same given equation.
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Sec(x/2) = 1/cos(x/2)
sec(x/2)=cos(x/2) ----> cos^2(x/2)=1 ---> cos(x/2) = -1 and cos(x/2) = 1
Cos(x/2)=1 --- > x/2 = 0, only. x = 0;
cos(x/2)=-1 ----> x/2 = pi -> x = 2pi. But the statement says [0,2pi), so 2pi can not be chosen.
Only x = 0.
In fact, your equation is equivalent to sec(x)=cos(x), for x in [ 0, pi), so yes, only x = 0 .