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### Task 5

(a) Copy and complete the following table for the relation [tex]\( y = \frac{5}{2} + x - 4 \)[/tex].

[tex]\[
\begin{array}{c|c|c|c|c|c|c|c|c}
x & -2.0 & -1.5 & -1.0 & -0.5 & 0 & 0.5 & 1 & 1.5 \\
\hline
y & -15.5 & & & 1 & 2.5 & & & \\
\end{array}
\][/tex]

(b) Using a scale of 2 cm to 1 unit on the [tex]\( x \)[/tex]-axis and 2 cm to 5 units on the [tex]\( y \)[/tex]-axis, draw the graph of the relation for [tex]\( -2.0 \leq x \leq 2.0 \)[/tex].

(c) What is the maximum value of [tex]\( y \)[/tex]?

(d) From your graph, obtain the roots of the equation [tex]\( 8x^2 - 2x - 5 = 0 \)[/tex].


Sagot :

### 5 (a)
First, we complete the given table for the relation [tex]\( y = \frac{5}{2} + x - 4 \)[/tex]:

[tex]\[ \begin{array}{c|c|c|c|c|c|c|c|c} x & -2.0 & -1.5 & -1.0 & -0.5 & 0 & 0.5 & 1 & 1.5 \\ \hline y & -15.5 & -3.0 & -2.5 & 1 & 2.5 & -1.0 & -0.5 & 0.0 \\ \end{array} \][/tex]

Note that some values of [tex]\( y \)[/tex] were already provided, and others were calculated.

### 5 (b)
To draw the graph of the relation [tex]\( y = \frac{5}{2} + x - 4 \)[/tex] for [tex]\( -2.0 \leq x \leq 2.0 \)[/tex], follow these steps:

1. Set up your coordinate system with the scales:
- On the X-axis, use a scale of 2 cm for each unit.
- On the Y-axis, use a scale of 2 cm for every 5 units.

2. Plot the points from the completed table:

| [tex]\(x\)[/tex] | [tex]\(y\)[/tex] |
|-------|---------|
| -2.0 | -15.5 |
| -1.5 | -3.0 |
| -1.0 | -2.5 |
| -0.5 | 1 |
| 0 | 2.5 |
| 0.5 | -1.0 |
| 1 | -0.5 |
| 1.5 | 0.0 |

3. Plot these points on the graph paper accordingly.

4. Draw a smooth line joining these points to represent the relation.

### 5 (c)
The maximum value of [tex]\( y \)[/tex] can be observed from the table, which is:
[tex]\[ \boxed{2.5} \][/tex]

### 5 (d)
To find the roots of the equation [tex]\( 8x^2 - 2x - 5 = 0 \)[/tex]:

1. From the table, the maximum value is [tex]\( y = 2.5 \)[/tex]. However, for the roots of the given quadratic equation, we solve for [tex]\( x \)[/tex].

2. The roots of the equation [tex]\( 8x^2 - 2x - 5 = 0 \)[/tex] are:
[tex]\[ \boxed{\frac{1}{8} - \frac{\sqrt{41}}{8}, \quad \frac{1}{8} + \frac{\sqrt{41}}{8}} \][/tex]

These steps provide a comprehensive solution and the necessary steps to answer each part of the problem effectively.