The problem consists of three parts. Part (a) asks to complete a table of values for the equation $y = 2x^2 - 7x - 9$ for $-3 \le x \le 6$. Part (b) asks to draw the graph of the equation using given scales. Part (c) asks to use the graph to estimate the roots of $2x^2 - 7x = 26$, the coordinates of the minimum point of $y$, and the range of values for which $2x^2 - 7x < 9$.
2025/4/10
1. Problem Description
The problem consists of three parts. Part (a) asks to complete a table of values for the equation for . Part (b) asks to draw the graph of the equation using given scales. Part (c) asks to use the graph to estimate the roots of , the coordinates of the minimum point of , and the range of values for which .
2. Solution Steps
(a) Completing the table of values:
We need to calculate the values of for .
For :
For :
For :
For :
For :
Completed table:
x | -3 | -2 | -1 | 0 | 1 | 2 | 3 | 4 | 5 | 6
--|----|----|----|---|---|---|---|---|---|---
y | 30 | 13 | 0 | -9| -14| -15| -12| -5| 6 | 21
(b) Drawing the graph:
Using the table of values, plot the points on a graph with a scale of 2 cm to 1 unit on the x-axis and 2 cm to 4 units on the y-axis. Draw a smooth curve through the points.
Since I cannot draw the graph, I will proceed with part (c) assuming we have the graph.
(c) Using the graph to estimate:
(i) Roots of the equation :
Rewrite the equation as . We want to find the values of when . Find the points on the graph where . The x-coordinates of these points are the roots. From the graph (which I cannot provide), let's assume these roots are approximately and .
(ii) Coordinates of the minimum point of :
The minimum point of the graph is the vertex of the parabola. Visually estimate the coordinates of the lowest point on the curve. From the graph (which I cannot provide), let's assume this point is approximately .
(iii) Range of values for which :
Rewrite the inequality as , which is equivalent to . Find the points on the graph where . These are the roots of the equation . These roots are and . The range of values for for which is between these roots. So .
3. Final Answer
(a) Completed table:
x | -3 | -2 | -1 | 0 | 1 | 2 | 3 | 4 | 5 | 6
--|----|----|----|---|---|---|---|---|---|---
y | 30 | 13 | 0 | -9| -14| -15| -12| -5| 6 | 21
(b) Graph (cannot be drawn).
(c) Estimates from the graph (approximate values):
(i) Roots of : and
(ii) Coordinates of the minimum point of :
(iii) Range of values for which :