Question

Problem 4) Suppose a parabola is graphed with the equation y=−18x2+34x+78
. Find the value of y when x = 3.(1 point)
Responses

y = 1
y = 1

y = 2
y = 2

y = 3
y = 3

y = 4

Answer 1

To find the value of \( y \) when \( x = 3 \) for the parabola with the equation \( y = -18x^2 + 34x + 78 \), we can substitute \( x = 3 \) into the equation:

\[
y = -18(3)^2 + 34(3) + 78
\]

Calculating \( (3)^2 \):

\[
(3)^2 = 9
\]

Now substitute this value into the equation:

\[
y = -18(9) + 34(3) + 78
\]

Calculating \( -18(9) \):

\[
-18(9) = -162
\]

Calculating \( 34(3) \):

\[
34(3) = 102
\]

Now substitute these values into the equation:

\[
y = -162 + 102 + 78
\]

Now compute \( -162 + 102 \):

\[
-162 + 102 = -60
\]

Finally, add \( -60 + 78 \):

\[
-60 + 78 = 18
\]

Thus, when \( x = 3 \), \( y = 18 \).

Since 18 is not in the provided options, it appears there may have been a miscommunication. The result of \( y \) at \( x = 3 \) is indeed \( 18 \).