Answer:
x = 1.434 and x=0.232
Step-by-step explanation:
To find the root of the equation stated above we need to:
(1) Write the polynomial equation with zero on the right hand side:
⇒ 
(2) Divide the whole equation by 3
⇒ 
(3) Use the quadratic formula to solve the quadratic equation:
The quadratic formula states that the two solutions for a quadratic equation is given by:
(1)
In this case, a = 1, b = 
Substituiting a, b and c in equation (1) We get:
(1)
The two solutions are:
x = 1.434 and x=0.232
Not equivalent to any of the given expressions.
Step-by-step explanation:

Hence,
is not equivalent to any of the given expressions.
First, you need to write to expressions to model each situation:
Plan A: 10+0.15x
Plan B: 30+0.1x
Next, set the expressions equal to each other and solve for x:
10+0.15x=30+0.1x
<em>*Subtract 0.1x from both sides to isolate the variable*</em>
10+0.05x=30
<em>*Subtract 10 from both sides*</em>
0.05x=20
<em>*Divide both sides by 0.05*</em>
x=400
The plans would have the same cost after 400 minutes of calls.
To find how much money the plans cost at 400 minutes, plug 400 into either expression. We'll use Plan A:
10+0.15(400)
10+60
70
The plans will cost $70.
Hope this helps!
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