Find the value of `3x^2-5x+8` for x=3

Answer

To find the value of the expression \(3x^2 - 5x + 8\) for \(x = 3\), we will substitute \(3\) into the expression and simplify step by step.

### Step-by-Step Solution:

1. **Write down the expression**:
\[ 3x^2 - 5x + 8 \]

2. **Substitute \(x = 3\)** into the expression:
\[ 3(3^2) - 5(3) + 8 \]

3. **Calculate \(3^2\)**:
\[ 3^2 = 9 \]
So, the expression now becomes:
\[ 3(9) - 5(3) + 8 \]

4. **Multiply \(3\) by \(9\)**:
\[ 3 \times 9 = 27 \]
Now the expression is:
\[ 27 - 5(3) + 8 \]

5. **Calculate \(5(3)\)**:
\[ 5 \times 3 = 15 \]
Now the expression is:
\[ 27 - 15 + 8 \]

6. **Subtract \(15\) from \(27\)**:
\[ 27 - 15 = 12 \]
Now the expression is:
\[ 12 + 8 \]

7. **Add \(8\) to \(12\)**:
\[ 12 + 8 = 20 \]

### Final Answer:
The value of \(3x^2 - 5x + 8\) for \(x = 3\) is \(20\).

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