Question

Mr. Pham wrote the equation below on the board.

18 minus 7 x = negative 20.5

What is the value of x?
Negative 5 and one-half
Negative StartFraction 5 Over 14 EndFraction
StartFraction 5 Over 14 EndFraction
5 and one-half

Answer 1

To solve the equation \(18 - 7x = -20.5\), we can follow these steps:

1. Isolate the term with \(x\) on one side. Start by subtracting 18 from both sides:
\[
18 - 7x - 18 = -20.5 - 18
\]
This simplifies to:
\[
-7x = -20.5 - 18
\]
Calculate \(-20.5 - 18\):
\[
-20.5 - 18 = -38.5
\]
So now we have:
\[
-7x = -38.5
\]

2. Now, divide both sides by -7 to solve for \(x\):
\[
x = \frac{-38.5}{-7} = \frac{38.5}{7}
\]

3. Convert 38.5 to a fraction:
\[
38.5 = \frac{385}{10} = \frac{77}{2}
\]
So,
\[
x = \frac{77/2}{7} = \frac{77}{2} \cdot \frac{1}{7} = \frac{77}{14}
\]

4. Simplify \(\frac{77}{14}\):
\[
x = \frac{77}{14} = 5.5
\]

Thus, the value of \(x\) is \(5.5\) or \(5 \frac{1}{2}\).

Therefore, the correct answer is:
**5 and one-half.**