Answer :

Sure, let's solve the equation step-by-step.

Given equation:

[tex]\[ -2(2x - 5) - 18 = 0 \][/tex]

First, distribute the -2 across the parentheses:

[tex]\[ -2 \cdot 2x - (-2 \cdot 5) - 18 = 0 \][/tex]

This simplifies to:

[tex]\[ -4x + 10 - 18 = 0 \][/tex]

Combine the constants:

[tex]\[ -4x - 8 = 0 \][/tex]

Next, isolate [tex]\( x \)[/tex] by adding 8 to both sides:

[tex]\[ -4x = 8 \][/tex]

Then, divide both sides by -4:

[tex]\[ x = -2 \][/tex]

So, the value of [tex]\( x \)[/tex] is:

[tex]\[ x = -2 \][/tex]

Now, let's find the value when [tex]\( b = 3 \)[/tex]. Here, interpret the equation [tex]\( -2(2x - 5) - 18 = 0 \)[/tex] in terms of [tex]\( b \)[/tex]:

First, substitute [tex]\( b = 3 \)[/tex] into the equation. This yields:

[tex]\[ -2(2 \cdot 3 - 5) - 18 \][/tex]

Calculate inside the parentheses first:

[tex]\[ 2 \cdot 3 = 6 \][/tex]

[tex]\[ 6 - 5 = 1 \][/tex]

Now, replace the simplified terms back into the equation:

[tex]\[ -2 \cdot 1 - 18 \][/tex]

Multiply:

[tex]\[ -2 \cdot 1 = -2 \][/tex]

Finally,

[tex]\[ -2 - 18 = -20 \][/tex]

Now, negating -20, we have:

[tex]\[ 20 \][/tex]

So, when [tex]\( b = 3 \)[/tex]:

[tex]\[ x = 20 \][/tex]

Thus, the complete answers are:

- The value of [tex]\( x \)[/tex] is [tex]\( -2 \)[/tex].
- The value of [tex]\( x \)[/tex] when [tex]\( b = 3 \)[/tex] is [tex]\( 20 \)[/tex].