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 $2x^2 - 7x < 9$.

AlgebraQuadratic EquationsGraphingParabolaInequalitiesFunction Analysis
2025/4/10

1. Problem Description

The problem consists of three parts. Part (a) asks to complete a table of values for the equation y=2x27x9y = 2x^2 - 7x - 9 for 3x6-3 \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 2x27x=262x^2 - 7x = 26, the coordinates of the minimum point of yy, and the range of values for which 2x27x<92x^2 - 7x < 9.

2. Solution Steps

(a) Completing the table of values:
We need to calculate the values of yy for x=3,1,2,4,6x = -3, -1, 2, 4, 6.
For x=3x = -3:
y=2(3)27(3)9=2(9)+219=18+219=30y = 2(-3)^2 - 7(-3) - 9 = 2(9) + 21 - 9 = 18 + 21 - 9 = 30
For x=1x = -1:
y=2(1)27(1)9=2(1)+79=2+79=0y = 2(-1)^2 - 7(-1) - 9 = 2(1) + 7 - 9 = 2 + 7 - 9 = 0
For x=2x = 2:
y=2(2)27(2)9=2(4)149=8149=15y = 2(2)^2 - 7(2) - 9 = 2(4) - 14 - 9 = 8 - 14 - 9 = -15
For x=4x = 4:
y=2(4)27(4)9=2(16)289=32289=5y = 2(4)^2 - 7(4) - 9 = 2(16) - 28 - 9 = 32 - 28 - 9 = -5
For x=6x = 6:
y=2(6)27(6)9=2(36)429=72429=21y = 2(6)^2 - 7(6) - 9 = 2(36) - 42 - 9 = 72 - 42 - 9 = 21
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 2x27x=262x^2 - 7x = 26:
Rewrite the equation as 2x27x26=02x^2 - 7x - 26 = 0. We want to find the values of xx when y=2x27x9=269=17y = 2x^2 - 7x - 9 = 26 - 9 = 17. Find the points on the graph where y=17y = 17. The x-coordinates of these points are the roots. From the graph (which I cannot provide), let's assume these roots are approximately x2.2x \approx -2.2 and x5.7x \approx 5.7.
(ii) Coordinates of the minimum point of yy:
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 (1.75,15.1)(1.75, -15.1).
(iii) Range of values for which 2x27x<92x^2 - 7x < 9:
Rewrite the inequality as 2x27x9<02x^2 - 7x - 9 < 0, which is equivalent to y<0y < 0. Find the points on the graph where y=0y=0. These are the roots of the equation 2x27x9=02x^2 - 7x - 9 = 0. These roots are x=1x=-1 and x=4.5x=4.5. The range of values for xx for which y<0y < 0 is between these roots. So 1<x<4.5-1 < x < 4.5.

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 2x27x=262x^2 - 7x = 26: x2.2x \approx -2.2 and x5.7x \approx 5.7
(ii) Coordinates of the minimum point of yy: (1.75,15.1)(1.75, -15.1)
(iii) Range of values for which 2x27x<92x^2 - 7x < 9: 1<x<4.5-1 < x < 4.5

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