Given the quadratic equation y=5x2+8x+9

𝑦
=
5
𝑥
2
+
8
𝑥
+
9
, solve for the y-coordinate of the parabola when x=−3
𝑥
=

3
.(1 point)
(−3

3
,)

1 answer

To find the y-coordinate of the parabola given the quadratic equation \( y = 5x^2 + 8x + 9 \) when \( x = -3 \), we can substitute \(-3\) for \(x\) in the equation:

\[ y = 5(-3)^2 + 8(-3) + 9 \]

Calculating each term:

  1. \( (-3)^2 = 9 \)
  2. \( 5(-3)^2 = 5 \times 9 = 45 \)
  3. \( 8(-3) = -24 \)

Now, substituting these values back into the equation:

\[ y = 45 - 24 + 9 \]

Now, compute:

\[ y = 45 - 24 = 21 \]

\[ y = 21 + 9 = 30 \]

Thus, when \( x = -3 \), the y-coordinate of the parabola is \( y = 30 \).

Therefore, the point is:

\[ (-3, 30) \]