Question

if $y = 2x^2 - 4x - 5$ what is the value when $x = -3$
20
25
15
30

Explanation:

Step1: Substitute \( x = -3 \) into the equation

We have the equation \( y = 2x^2 - 4x - 5 \). Substitute \( x = -3 \) into it:
\( y = 2(-3)^2 - 4(-3) - 5 \)

Step2: Calculate each term

First, calculate \( (-3)^2 = 9 \), so \( 2(-3)^2 = 2\times9 = 18 \).
Then, \( -4(-3) = 12 \).

Step3: Combine the terms

Now, substitute these values back into the equation:
\( y = 18 + 12 - 5 \)
First, \( 18 + 12 = 30 \), then \( 30 - 5 = 25 \).

Answer:

25