Question

Use the parabola tool to graph the quadratic function y=-1? - 2.0 +8

Graph the parabola by first plotting its vertex and then plotting a second point on the parabola.

Answer 1

see explanation

Explanation:

I don't have graphing facilities but can give you the vertex and 1 other point.

Given a parabola in standard form

y = ax² + bx + c ( a ≠ 0 )

Then the x- coordinate of the vertex is

x = -
`(b)/(2a)`

y = - x² - 2x + 8 ← is in standard form

with a = - 1 and b = - 2 , then

x = -
`(-2)/(-2)` = - 1

Substitute x = - 1 into the equation for corresponding value of y

y = - (- 1)² - 2(- 1) + 8 = - 1 + 2 + 8 = 9

vertex = (- 1, 9 )

To obtain another point substitute any value for x into the equation

x = 0 : y = 0 - 0 + 8 , then (0, 8 ) is a point on the graph

x = 2 : y = - (2)² - 2(2) + 8 = - 4 - 4 + 8 = 0 then (2, 0 ) is a point on the graph