If `(64)^2-(36)^2=20xx x, " then " x=?`

Options

A. 70
B. 120
C. 180
D. 140

Answer

To solve the equation \( (64)^2 - (36)^2 = 20x \), we can follow these steps:

### Step 1: Calculate \( (64)^2 \) and \( (36)^2 \)
First, we need to find the squares of 64 and 36.

\[ (64)^2 = 64 \times 64 = 4096 \]
\[ (36)^2 = 36 \times 36 = 1296 \]

### Step 2: Subtract the two squares
Now, we will subtract \( (36)^2 \) from \( (64)^2 \).

\[ (64)^2 - (36)^2 = 4096 - 1296 \]

Calculating the subtraction:

\[ 4096 - 1296 = 2800 \]

### Step 3: Set the equation equal to \( 20x \)
Now we can set up the equation based on the original problem:

\[ 2800 = 20x \]

### Step 4: Solve for \( x \)
To find \( x \), we will divide both sides of the equation by 20.

\[ x = \frac{2800}{20} \]

Calculating the division:

\[ x = 140 \]

### Final Answer
Thus, the value of \( x \) is:

\[ \boxed{140} \]