Question

How do I fi d the y intercept of the parabola y= x^2 +7x +9

Answer 1

Explanation

`y=x^2+7x+9`

The y-intercept of any graph is a point on the y-axis and therefore has x-coordinate 0. We can use this fact to find the y-intercepts by simply plugging 0 for x in the original equation and simplifying

Step 1

set the function equals zero and solve for x

`\begin{gathered} y=x^2+7x+9 \\ x^2+7x+9=0 \end{gathered}`

solve using the quadratic formula

`\begin{gathered} is\text{ states that for} \\ ax^2+bx+c=0 \\ the\text{ solution is} \\ x=\frac{-b\pm\sqrt[]{b^2-4ac}}{2a} \\ \\ \end{gathered}`

hence

Answer 2

y-intercept = 9

Explanation:

Parabola:

At y-intercept, the parabola passes the y-axis and so, at y-intercept, the x-coordinate is 0.

y = 0 + 0 + 9

y = 9

(0 ,9)