Westonci.ca is your trusted source for accurate answers to all your questions. Join our community and start learning today! Our platform connects you with professionals ready to provide precise answers to all your questions in various areas of expertise. Join our Q&A platform to connect with experts dedicated to providing accurate answers to your questions in various fields.

Find the [tex]\(x\)[/tex]-intercepts of the parabola with vertex [tex]\((-2, -8)\)[/tex] and [tex]\(y\)[/tex]-intercept [tex]\((0, 4)\)[/tex]. Write your answer in the form: [tex]\(\left(x_1, y_1\right), \left(x_2, y_2\right)\)[/tex]. If necessary, round to the nearest hundredth.

Sagot :

To find the [tex]\( x \)[/tex]-intercepts of the parabola with the given properties, we will follow a systematic approach. The vertex of the parabola is [tex]\((-2, -8)\)[/tex] and the [tex]\( y \)[/tex]-intercept is [tex]\((0, 4)\)[/tex].

1. Write the equation of the parabola in vertex form:
The vertex form of a parabola is:
[tex]\[ y = a(x - h)^2 + k \][/tex]
where [tex]\((h, k)\)[/tex] is the vertex. For the given vertex [tex]\((-2, -8)\)[/tex], we have:
[tex]\[ y = a(x + 2)^2 - 8 \][/tex]

2. Substitute the [tex]\( y \)[/tex]-intercept to find the value of [tex]\( a \)[/tex]:
The parabola passes through the [tex]\( y \)[/tex]-intercept [tex]\((0, 4)\)[/tex]. Substitute [tex]\((0, 4)\)[/tex] into the equation:
[tex]\[ 4 = a(0 + 2)^2 - 8 \][/tex]
Simplify to solve for [tex]\( a \)[/tex]:
[tex]\[ 4 = a \cdot 4 - 8 \][/tex]
[tex]\[ 4 = 4a - 8 \][/tex]
[tex]\[ 4a = 12 \][/tex]
[tex]\[ a = 3 \][/tex]

3. Write the complete equation with [tex]\( a \)[/tex] determined:
Using [tex]\( a = 3 \)[/tex]:
[tex]\[ y = 3(x + 2)^2 - 8 \][/tex]

4. Set the equation equal to zero to find the [tex]\( x \)[/tex]-intercepts:
The [tex]\( x \)[/tex]-intercepts occur where [tex]\( y = 0 \)[/tex]:
[tex]\[ 0 = 3(x + 2)^2 - 8 \][/tex]
Solve for [tex]\( x \)[/tex]:
[tex]\[ 3(x + 2)^2 = 8 \][/tex]
[tex]\[ (x + 2)^2 = \frac{8}{3} \][/tex]
[tex]\[ x + 2 = \pm \sqrt{\frac{8}{3}} \][/tex]
[tex]\[ x = -2 \pm \sqrt{\frac{8}{3}} \][/tex]

5. Calculate the numerical values of the [tex]\( x \)[/tex]-intercepts:
[tex]\[ x_1 = -2 + \sqrt{\frac{8}{3}} \][/tex]
[tex]\[ x_2 = -2 - \sqrt{\frac{8}{3}} \][/tex]

Using approximate calculations, we get:
[tex]\[ \sqrt{\frac{8}{3}} \approx 1.63299316185545 \][/tex]
Therefore:
[tex]\[ x_1 = -2 + 1.63299316185545 \approx -0.367006838144548 \][/tex]
[tex]\[ x_2 = -2 - 1.63299316185545 \approx -3.63299316185545 \][/tex]

6. Write the [tex]\( x \)[/tex]-intercepts as coordinates:
[tex]\[ \left(x_1, 0\right), \left(x_2, 0\right) \Rightarrow (-0.37, 0), (-3.63, 0) \][/tex]

Therefore, the [tex]\( x \)[/tex]-intercepts of the parabola are [tex]\( \left(-3.63, 0\right) \)[/tex] and [tex]\( \left(-0.37, 0\right) \)[/tex].