We are given the equation $2.8x + 53 = 1000 - x = 3900$ and asked to solve for $x$. It seems like there is an error in the equation as it contains two equals signs. Assuming the problem intends for $2.8x + 53 = 1000 - x$ and $1000 - x = 3900$ we have two different equations that can be solved separately. However, it is more likely the first equal sign is the one intended and the $3900$ is separate. So we will solve $2.8x + 53 = 1000 - x$.

1. Problem Description

We are given the equation $2.8x + 53 = 1000 - x = 3900$ and asked to solve for $x$. It seems like there is an error in the equation as it contains two equals signs. Assuming the problem intends for $2.8x + 53 = 1000 - x$ and $1000 - x = 3900$ we have two different equations that can be solved separately.

However, it is more likely the first equal sign is the one intended and the $3900$ is separate. So we will solve $2.8x + 53 = 1000 - x$.

2. Solution Steps

We are solving $2.8x + 53 = 1000 - x$.

Step 1: Add $x$ to both sides of the equation.

$2.8x + x + 53 = 1000 - x + x$

$3.8x + 53 = 1000$

Step 2: Subtract $53$ from both sides of the equation.

$3.8x + 53 - 53 = 1000 - 53$

$3.8x = 947$

Step 3: Divide both sides by $3.8$.

$x = \frac{947}{3.8}$

$x = 249.2105263...$

3. Final Answer

The value of $x$ is approximately $249.21$.

$x = \frac{947}{3.8} = \frac{4735}{19}$

Final Answer: $x = \frac{4735}{19}$