Questions: Evaluate. -x^2-9x for x=-7

Transcript text: Evaluate. \[ -x^{2}-9 x \text { for } x=-7 \]

Solution

To evaluate the expression \(-x^{2} - 9x\) for \(x = -7\), we need to substitute \(x\) with \(-7\) and then perform the arithmetic operations.

Step 1: Substitute \( x = -7 \) into the expression

Given the expression \( -x^2 - 9x \), we substitute \( x = -7 \):

\[ -x^2 - 9x \quad \text{becomes} \quad -(-7)^2 - 9(-7) \]

Step 2: Calculate \( (-7)^2 \)

First, we calculate the square of \(-7\):

\[ (-7)^2 = 49 \]

Step 3: Apply the negative sign to the squared term

Next, we apply the negative sign to the squared term:

\[ -(-7)^2 = -49 \]

Step 4: Calculate \( 9 \times (-7) \)

Now, we calculate the product of \( 9 \) and \(-7\):

\[ 9 \times (-7) = -63 \]

Step 5: Combine the results

Finally, we combine the results from the previous steps:

\[ -49 - 63 = -112 \]

\[ \boxed{-112} \]

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