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The first step to solving a system of linear equations by substitution is to solve one of the equations for one of its variables. Solve the first equation in the system of equations that you selected above. Write the equation with an isolated variable as your response below. Do not use any spaces in your answer.

User Kolesar
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The first equation is simplified and the variable x is isolated, resulting in x = (x/2 - 21)/0.1 as the reduced form.

To solve the given linear equation by substitution, we first simplify the equation and then isolate the variable x.

The given equation is:

0.8(2x + x) + 3(7 - 4.1x) = (x + 21)/2

Simplifying both sides:

1.6x + 0.8x + 21 - 12.3x = (x + 21)/2

Combining like terms:

(1.6x + 0.8x - 12.3x) + 21 = (x + 21)/2

(0.1x) + 21 = (x + 21)/2

Now, isolate the variable x:

0.1x + 21 - 21 = (x + 21)/2 - 21

x = (x/2 - 21)/0.1

This is the reduced form of the first equation in the system, with x isolated.

The probable question may be:

Given the system of linear equations:

\[ \text{A) } 0.8(2x + x) + 3(7 - 4.1x) = \frac{x + 21}{2} \]

First step to solve the system by substitution:

Solve the first equation in the system for one of its variables. Write the equation with an isolated variable as your response below. Do not use any spaces in your answer.

User Tassos Bassoukos
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