What is the value of the expression below 7x 2 +9x−3 when x=3?

1 answer

To find the value of the expression \( 7x^2 + 9x - 3 \) when \( x = 3 \), we first substitute \( x \) with 3 in the expression.

  1. Substitute \( x \) with 3: \[ 7(3)^2 + 9(3) - 3 \]

  2. Calculate \( (3)^2 \): \[ 7 \cdot 9 + 9 \cdot 3 - 3 \]

  3. Now multiply: \[ 63 + 27 - 3 \]

  4. Add \( 63 \) and \( 27 \): \[ 90 - 3 \]

  5. Finally, subtract \( 3 \): \[ 87 \]

Thus, the value of the expression \( 7x^2 + 9x - 3 \) when \( x = 3 \) is \( \boxed{87} \).