Question

If f(x) = 2x^2- 7 and g(x) = 2x + 1, evaluate f(g(x)) when x = -3

Answer 1

Given:-

• 
  `\textsf{f ( x ) = 2x² - 7 }`

`\:`

• 
  `\textsf{g ( x ) = 2x + 1}`

`\:`

• 
  `\textsf{x = -3}`

`\:`

To find:-

• 
  `\textsf{f ( g ( x ) ) = ?}`

`\:`

Solution:-

• 
  `\textsf{f ( x ) = 2x² - 7 * g ( x ) = 2x + 1}`

`\:`

• 
  `\textsf{f ( g ( x ) ) = 2x² - 7 * 2x + 1}`

`\:`

as we know , the value of x is -3 then put it in the equation:

• 
  `\textsf{f ( g ( x ) ) = 2( -3 )² - 7 * 2( -3 )+ 1}`

`\:`

• 
  `\textsf{f ( g ( x ) ) = 2(-9 ) - 7 * -6 + 1}`

`\:`

• 
  `\textsf{f ( g ( x ) ) = -18 - 7 * -6 + 1}`

`\:`

• 
  `\textsf{f ( g ( x ) ) = -25 * -5}`

`\:`

• 
  `\fbox{ \textsf \red{f ( g ( x ) ) = 125 }}`

`\:`

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hope it helps! :)