IDNLearn.com is designed to help you find the answers you need quickly and easily. Our community is here to provide the comprehensive and accurate answers you need to make informed decisions.

Solve the following equations:

1. [tex]2 f^2 - 10 f + 8 = 0[/tex]
2. [tex]3 x^2 - 5 x = -4[/tex]
3. [tex]r^2 + 6 r + 9 = 0[/tex]
4. [tex]l^2 + 5 l + 10 = 0[/tex]


Sagot :

Sure, let's solve each quadratic equation step by step.

### 1. Solve the equation [tex]\(2 f^2 - 10 f + 8 = 0\)[/tex]:

To solve the quadratic equation of the form [tex]\(ax^2 + bx + c = 0\)[/tex]:

1. Identify the coefficients: [tex]\(a = 2\)[/tex], [tex]\(b = -10\)[/tex], and [tex]\(c = 8\)[/tex].
2. Use the quadratic formula: [tex]\(f = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\)[/tex].

[tex]\[ b^2 - 4ac = (-10)^2 - 4 \cdot 2 \cdot 8 = 100 - 64 = 36 \][/tex]

[tex]\[ f = \frac{10 \pm \sqrt{36}}{4} = \frac{10 \pm 6}{4} \][/tex]

So,

[tex]\[ f_1 = \frac{10 + 6}{4} = 4 \][/tex]
[tex]\[ f_2 = \frac{10 - 6}{4} = 1 \][/tex]

The solutions are [tex]\(f = 1\)[/tex] and [tex]\(f = 4\)[/tex].

### 2. Solve the equation [tex]\(3 x^2 - 5 x + 4 = 0\)[/tex]:

1. Rearrange terms if necessary and identify the coefficients: [tex]\(a = 3\)[/tex], [tex]\(b = -5\)[/tex], [tex]\(c = 4\)[/tex].
2. Use the quadratic formula: [tex]\(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\)[/tex].

[tex]\[ b^2 - 4ac = (-5)^2 - 4 \cdot 3 \cdot 4 = 25 - 48 = -23 \][/tex]

[tex]\[ x = \frac{5 \pm \sqrt{-23}}{6} = \frac{5 \pm \sqrt{23}i}{6} \][/tex]

The solutions are:

[tex]\[ x_1 = \frac{5 - \sqrt{23}i}{6} \][/tex]
[tex]\[ x_2 = \frac{5 + \sqrt{23}i}{6} \][/tex]

### 3. Solve the equation [tex]\(r^2 + 6 r + 9 = 0\)[/tex]:

1. Identify the coefficients: [tex]\(a = 1\)[/tex], [tex]\(b = 6\)[/tex], and [tex]\(c = 9\)[/tex].
2. Use the quadratic formula: [tex]\(r = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\)[/tex].

Since this is a perfect square trinomial, we can also see,

[tex]\[ b^2 - 4ac = 6^2 - 4 \cdot 1 \cdot 9 = 36 - 36 = 0 \][/tex]

[tex]\[ r = \frac{-6 \pm \sqrt{0}}{2} = \frac{-6}{2} = -3 \][/tex]

The solution is [tex]\(r = -3\)[/tex]. Note that this is a repeated root.

### 4. Solve the equation [tex]\(l^2 + 5 l + 10 = 0\)[/tex]:

1. Identify the coefficients: [tex]\(a = 1\)[/tex], [tex]\(b = 5\)[/tex], and [tex]\(c = 10\)[/tex].
2. Use the quadratic formula: [tex]\(l = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\)[/tex].

[tex]\[ b^2 - 4ac = 5^2 - 4 \cdot 1 \cdot 10 = 25 - 40 = -15 \][/tex]

[tex]\[ l = \frac{-5 \pm \sqrt{-15}}{2} = \frac{-5 \pm \sqrt{15}i}{2} \][/tex]

The solutions are:

[tex]\[ l_1 = \frac{-5 - \sqrt{15}i}{2} \][/tex]
[tex]\[ l_2 = \frac{-5 + \sqrt{15}i}{2} \][/tex]

So, to summarize, the solutions for each quadratic equation are:
1. [tex]\( f = 1 \)[/tex], [tex]\( f = 4 \)[/tex]
2. [tex]\( x = \frac{5 - \sqrt{23}i}{6} \)[/tex], [tex]\( x = \frac{5 + \sqrt{23}i}{6} \)[/tex]
3. [tex]\( r = -3 \)[/tex]
4. [tex]\( l = \frac{-5 - \sqrt{15}i}{2} \)[/tex], [tex]\( l = \frac{-5 + \sqrt{15}i}{2} \)[/tex]