1) If [tex]$\alpha$[/tex] and [tex]$\beta$[/tex] are zeros of the polynomial [tex]$3x^2 + 2x - 6$[/tex], then find:

(a) [tex]$\alpha + \beta$[/tex]

(b) [tex]$\frac{1}{\alpha} + \frac{1}{\beta}$[/tex]

(c) [tex]$\alpha + \beta + \alpha \beta$[/tex]



Answer :

Sure! Let's solve the problem step-by-step.

Given the polynomial [tex]\(3x^2 + 2x - 6\)[/tex], we need to find the following:
(a) [tex]\(\alpha + \beta\)[/tex]
(b) [tex]\(\frac{1}{\alpha} + \frac{1}{\beta}\)[/tex]
(c) [tex]\(\alpha + \beta + \alpha\beta\)[/tex]

### Step 1: Finding [tex]\(\alpha + \beta\)[/tex]
For a quadratic polynomial [tex]\(ax^2 + bx + c\)[/tex], the sum of the zeroes, [tex]\(\alpha + \beta\)[/tex], is given by:
[tex]\[ \alpha + \beta = -\frac{b}{a} \][/tex]
Here, [tex]\(a = 3\)[/tex], [tex]\(b = 2\)[/tex], and [tex]\(c = -6\)[/tex]. Plugging in the values:
[tex]\[ \alpha + \beta = -\frac{2}{3} \][/tex]
Thus, [tex]\(\alpha + \beta = -0.6666666666666666\)[/tex].

### Step 2: Finding [tex]\(\frac{1}{\alpha} + \frac{1}{\beta}\)[/tex]
The sum of the reciprocals of the zeroes is given by:
[tex]\[ \frac{1}{\alpha} + \frac{1}{\beta} = \frac{\alpha + \beta}{\alpha\beta} \][/tex]
We already know [tex]\(\alpha + \beta = -0.6666666666666666\)[/tex]. Next, we need to find [tex]\(\alpha\beta\)[/tex].

### Step 3: Finding [tex]\(\alpha\beta\)[/tex]
For a quadratic polynomial [tex]\(ax^2 + bx + c\)[/tex], the product of the zeroes, [tex]\(\alpha\beta\)[/tex], is given by:
[tex]\[ \alpha\beta = \frac{c}{a} \][/tex]
Plugging in the values:
[tex]\[ \alpha\beta = \frac{-6}{3} = -2 \][/tex]
Thus, [tex]\(\alpha\beta = -2\)[/tex].

### Step 4: Computing [tex]\(\frac{1}{\alpha} + \frac{1}{\beta}\)[/tex]
Using the values obtained:
[tex]\[ \frac{1}{\alpha} + \frac{1}{\beta} = \frac{\alpha + \beta}{\alpha\beta} = \frac{-0.6666666666666666}{-2} = 0.3333333333333333 \][/tex]

### Step 5: Finding [tex]\(\alpha + \beta + \alpha\beta\)[/tex]
This is a simple addition of the already known values of [tex]\(\alpha + \beta\)[/tex] and [tex]\(\alpha\beta\)[/tex]:
[tex]\[ \alpha + \beta + \alpha\beta = (-0.6666666666666666) + (-2) = -2.6666666666666665 \][/tex]

### Conclusion
(a) [tex]\(\alpha + \beta = -0.6666666666666666\)[/tex]

(b) [tex]\(\frac{1}{\alpha} + \frac{1}{\beta} = 0.3333333333333333\)[/tex]

(c) [tex]\(\alpha + \beta + \alpha\beta = -2.6666666666666665\)[/tex]