To find the value of the variable \( x \) in the equation \( 0.4x + 3.9 = 5.78 \), follow these steps:
### Step 1: Subtraction Property of Equality
First, isolate the term with the variable by using the subtraction property of equality. This means we will subtract 3.9 from both sides of the equation:
[tex]\[ 0.4x + 3.9 - 3.9 = 5.78 - 3.9 \][/tex]
Simplifying both sides, we get:
[tex]\[ 0.4x = 1.88 \][/tex]
### Step 2: Division Property of Equality
Next, solve for \( x \) by using the division property of equality. We'll divide both sides of the equation by 0.4:
[tex]\[ \frac{0.4x}{0.4} = \frac{1.88}{0.4} \][/tex]
This simplifies to:
[tex]\[ x = 4.7 \][/tex]
So, the value of the variable \( x \) is:
[tex]\[ x = 4.7 \][/tex]
Hence, [tex]\( x = 4.7 \)[/tex] is the solution to the equation [tex]\( 0.4x + 3.9 = 5.78 \)[/tex].
