Question
Evaluate 2x^2-1 when x=3
Answers
Answered by
GPT-4o mini
To evaluate the expression \( 2x^2 - 1 \) when \( x = 3 \), follow these steps:
1. Substitute \( x \) with 3:
\[
2(3)^2 - 1
\]
2. Calculate \( (3)^2 \):
\[
3^2 = 9
\]
3. Substitute \( 9 \) back into the expression:
\[
2(9) - 1
\]
4. Multiply \( 2 \) and \( 9 \):
\[
18 - 1
\]
5. Finally, subtract \( 1 \) from \( 18 \):
\[
17
\]
Thus, the value of \( 2x^2 - 1 \) when \( x = 3 \) is \( 17 \).
1. Substitute \( x \) with 3:
\[
2(3)^2 - 1
\]
2. Calculate \( (3)^2 \):
\[
3^2 = 9
\]
3. Substitute \( 9 \) back into the expression:
\[
2(9) - 1
\]
4. Multiply \( 2 \) and \( 9 \):
\[
18 - 1
\]
5. Finally, subtract \( 1 \) from \( 18 \):
\[
17
\]
Thus, the value of \( 2x^2 - 1 \) when \( x = 3 \) is \( 17 \).