Find the value of :
`2x^(4)-5x^(3)+7x-3` where x=-3

Answer

To find the value of the expression \(2x^4 - 5x^3 + 7x - 3\) when \(x = -3\), we will substitute \(-3\) into the expression and simplify step by step.

### Step-by-Step Solution:

1. **Substitute \(x = -3\) into the expression:**
\[ 2(-3)^4 - 5(-3)^3 + 7(-3) - 3 \]

2. **Calculate \((-3)^4\):**
\[ (-3)^4 = 81 \quad \text{(since the power is even, the result is positive)} \]

3. **Calculate \((-3)^3\):**
\[ (-3)^3 = -27 \quad \text{(since the power is odd, the result is negative)} \]

4. **Substitute these values back into the expression:**
\[ 2(81) - 5(-27) + 7(-3) - 3 \]

5. **Multiply:**
- Calculate \(2 \times 81\):
\[ 2 \times 81 = 162 \]
- Calculate \(-5 \times -27\):
\[ -5 \times -27 = 135 \quad \text{(negative times negative is positive)} \]
- Calculate \(7 \times -3\):
\[ 7 \times -3 = -21 \]

6. **Now substitute these results back into the expression:**
\[ 162 + 135 - 21 - 3 \]

7. **Combine the values:**
- First, add \(162 + 135\):
\[ 162 + 135 = 297 \]
- Then subtract \(21\):
\[ 297 - 21 = 276 \]
- Finally, subtract \(3\):
\[ 276 - 3 = 273 \]

8. **Final Result:**
\[ \text{The value of the expression is } 273. \]