Answer:
Vertex form: y = -23(x + 1)² + 22
Standard form: y = -23x² - 46x - 1
Roots at (-1.978, 0) and (-0.022, 0)
Step-by-step explanation:
The vertex form of the equation for a parabola is
y = a(x - h)² + k
where h and k are the coordinates of the vertex and a is a constant.
Data:
Vertex at (-1,22)
y-intercept at (0, -1)
Calculations:
1. Substitute the coordinates of the vertex into the equation
y = a(x + 1)² + 22
2. Substitute the coordinates of the y-intercept into the equation and solve for a
![\begin{array}{rcl}y&=& a(x +1)^{2} + 22\\-1 & = & a(0 +1)^{2} + 22\\-1 & = & a(1)^{2} + 22\\-1 & = & a+ 22\\\mathbf{a} & = &\mathbf{-23}\\\end{array}](https://tex.z-dn.net/?f=%5Cbegin%7Barray%7D%7Brcl%7Dy%26%3D%26%20a%28x%20%2B1%29%5E%7B2%7D%20%2B%2022%5C%5C-1%20%26%20%3D%20%26%20a%280%20%2B1%29%5E%7B2%7D%20%2B%2022%5C%5C-1%20%26%20%3D%20%26%20a%281%29%5E%7B2%7D%20%2B%2022%5C%5C-1%20%26%20%3D%20%26%20a%2B%2022%5C%5C%5Cmathbf%7Ba%7D%20%26%20%3D%20%26%5Cmathbf%7B-23%7D%5C%5C%5Cend%7Barray%7D)
The equation of the parabola in vertex form is
y = -23(x + 1)² + 22
To convert the equation to standard form, you expand the vertex form.
![\begin{array}{rcl}y & = & -23(x + 1)^{2} + 22\\y & = & -23(x^{2} + 2x + 1) + 22\\y & = & -23x^{2} - 46x - 23 + 22\\\mathbf{y} & = &\mathbf{-23x^{2} - 46x - 1}\\\end{array}](https://tex.z-dn.net/?f=%5Cbegin%7Barray%7D%7Brcl%7Dy%20%26%20%3D%20%26%20-23%28x%20%2B%201%29%5E%7B2%7D%20%2B%2022%5C%5Cy%20%26%20%3D%20%26%20-23%28x%5E%7B2%7D%20%2B%202x%20%2B%201%29%20%2B%2022%5C%5Cy%20%26%20%3D%20%26%20-23x%5E%7B2%7D%20-%2046x%20-%2023%20%2B%2022%5C%5C%5Cmathbf%7By%7D%20%26%20%3D%20%26%5Cmathbf%7B-23x%5E%7B2%7D%20-%2046x%20-%201%7D%5C%5C%5Cend%7Barray%7D)
The equation of the parabola in standard form is
y = -23x² - 46x - 1
3. Find the roots
The roots are the values of x that make y = 0
![\begin{array}{rcl}0 & = & -23(x + 1)^{2} + 22\\23(x + 1)^{2} & = & 22\\(x + 1)^{2} & = & \dfrac{22}{23}\\\\x + 1 & = & \pm \sqrt{\dfrac{22}{23}}\\\\x & = & -1 \pm \sqrt{\dfrac{22}{23}}\\\\x = -1-\sqrt{\dfrac{22}{23}} && x = -1+\sqrt{\dfrac{22}{23}}\\\\x = -1-0.978 && x = -1+0.978\\\mathbf{x= -1.978} && \mathbf{x = -0.022}\\\end{array}](https://tex.z-dn.net/?f=%5Cbegin%7Barray%7D%7Brcl%7D0%20%26%20%3D%20%26%20-23%28x%20%2B%201%29%5E%7B2%7D%20%2B%2022%5C%5C23%28x%20%2B%201%29%5E%7B2%7D%20%20%26%20%3D%20%26%2022%5C%5C%28x%20%2B%201%29%5E%7B2%7D%20%20%26%20%3D%20%26%20%5Cdfrac%7B22%7D%7B23%7D%5C%5C%5C%5Cx%20%2B%201%20%26%20%3D%20%26%20%5Cpm%20%5Csqrt%7B%5Cdfrac%7B22%7D%7B23%7D%7D%5C%5C%5C%5Cx%20%26%20%3D%20%26%20-1%20%5Cpm%20%5Csqrt%7B%5Cdfrac%7B22%7D%7B23%7D%7D%5C%5C%5C%5Cx%20%3D%20-1-%5Csqrt%7B%5Cdfrac%7B22%7D%7B23%7D%7D%20%26%26%20x%20%3D%20-1%2B%5Csqrt%7B%5Cdfrac%7B22%7D%7B23%7D%7D%5C%5C%5C%5Cx%20%3D%20-1-0.978%20%26%26%20x%20%3D%20-1%2B0.978%5C%5C%5Cmathbf%7Bx%3D%20-1.978%7D%20%26%26%20%5Cmathbf%7Bx%20%3D%20-0.022%7D%5C%5C%5Cend%7Barray%7D)
The roots are at x = -1.978 and x = -0.022.
The graph shows your parabola with vertex (-1, 22), y-intercept at (0, -1). and x-intercepts at (-1.978, 0) and (-0.022, 0).