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Please help thank youuu

Please help thank youuu-example-1
User Jash
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1 Answer

3 votes

Answers are in bold

  • f(5) = -77
  • g(-4) = -4

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Step-by-step explanation:

The x is a placeholder for a number.

When we say f(5), we mean f(x) when x = 5

So we'll replace every copy of x with 5 like so...


f(\text{x}) = -3\text{x}^2 - 2\\\\f(5) = -3(5)^2 - 2\\\\f(5) = -3(25) - 2\\\\f(5) = -75 - 2\\\\f(5) = -77\\\\

Notice how I used the order of operations PEMDAS after x = 5 was plugged in.

A similar situation happens with g(-4). We'll plug x = -4 into g(x) to get the following:


g(\text{x}) = 2\text{x} +4\\\\g(-4) = 2(-4) +4\\\\g(-4) = -8 +4\\\\g(-4) = -4\\\\

You can use a graphing calculator or graphing software (eg: Desmos or GeoGebra) to confirm these answers quickly.

User TygerKrash
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4.2k points