Evaluate the expression when x= -6.
x² + 8x-9

-21.

Step-by-step explanation:

Evaluating an expression is very similar to solving an equation, just without an equal sign.

Start by plugging in the given x value into your expression

to

Because a negative multiplied by another negative or itself cancels the negatives out, and are the same when evaluated**.

Positive times negative makes negative, so is , which leaves

Then by simplifying, you get

and finally

Hope this helped!

**Be careful though, because and are not the same thing. is read as , which implies that you're squaring 6, but the ending value is negative.

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step-by-step explanation:

i used the pitagoras theoreme