1. Simplify the following expressions using surd laws. Show the expansion of the surds and all intermediate steps.

1.1. [tex]\(\frac{4-\sqrt{2}}{2+\sqrt{2}}\)[/tex]

1.2. [tex]\(2 \sqrt{2}-8 \sqrt{32}\)[/tex]

1.3. [tex]\(2 \sqrt{27}+6 \sqrt{48}+6 \sqrt{75}\)[/tex]



Answer :

Sure, let's simplify the given expressions step-by-step.

### 1.3.1. [tex]\(\frac{4 - \sqrt{2}}{2 + \sqrt{2}}\)[/tex]

To simplify this expression, we rationalize the denominator. We multiply both the numerator and the denominator by the conjugate of the denominator.

The conjugate of [tex]\( 2 + \sqrt{2} \)[/tex] is [tex]\( 2 - \sqrt{2} \)[/tex].

[tex]\[ \frac{4 - \sqrt{2}}{2 + \sqrt{2}} \times \frac{2 - \sqrt{2}}{2 - \sqrt{2}} = \frac{(4 - \sqrt{2})(2 - \sqrt{2})}{(2 + \sqrt{2})(2 - \sqrt{2})} \][/tex]

Now, we calculate the numerator and the denominator separately.

Numerator:

[tex]\[ (4 - \sqrt{2})(2 - \sqrt{2}) = 4 \cdot 2 + 4 \cdot (-\sqrt{2}) - \sqrt{2} \cdot 2 - \sqrt{2} \cdot (-\sqrt{2}) \][/tex]

[tex]\[ = 8 - 4\sqrt{2} - 2\sqrt{2} + 2 = 10 - 6\sqrt{2} \][/tex]

Denominator:

[tex]\[ (2 + \sqrt{2})(2 - \sqrt{2}) = 2^2 - (\sqrt{2})^2 = 4 - 2 = 2 \][/tex]

Putting the numerator and denominator together:

[tex]\[ \frac{10 - 6\sqrt{2}}{2} = 5 - 3\sqrt{2} \][/tex]

So, [tex]\(\frac{4 - \sqrt{2}}{2 + \sqrt{2}} = 5 - 3\sqrt{2}.\)[/tex]

### 1.3.2. [tex]\(2 \sqrt{2} - 8 \sqrt{32}\)[/tex]

We can simplify the surd [tex]\(\sqrt{32}\)[/tex]:

[tex]\[ \sqrt{32} = \sqrt{16 \cdot 2} = \sqrt{16} \cdot \sqrt{2} = 4\sqrt{2} \][/tex]

Now we substitute this back into the original expression:

[tex]\[ 2 \sqrt{2} - 8 \sqrt{32} = 2 \sqrt{2} - 8 \cdot 4\sqrt{2} = 2 \sqrt{2} - 32 \sqrt{2} \][/tex]

[tex]\[ = (2 - 32) \sqrt{2} = -30 \sqrt{2} \][/tex]

So, [tex]\(2 \sqrt{2} - 8 \sqrt{32} = -30 \sqrt{2}.\)[/tex]

### 1.3.3. [tex]\(2 \sqrt{27} + 6 \sqrt{48} + 6 \sqrt{75}\)[/tex]

We simplify each surd individually:

[tex]\[ \sqrt{27} = \sqrt{9 \cdot 3} = \sqrt{9} \cdot \sqrt{3} = 3\sqrt{3} \][/tex]

[tex]\[ \sqrt{48} = \sqrt{16 \cdot 3} = \sqrt{16} \cdot \sqrt{3} = 4\sqrt{3} \][/tex]

[tex]\[ \sqrt{75} = \sqrt{25 \cdot 3} = \sqrt{25} \cdot \sqrt{3} = 5\sqrt{3} \][/tex]

Now substitute these back into the original expression:

[tex]\[ 2 \sqrt{27} + 6 \sqrt{48} + 6 \sqrt{75} = 2 \cdot 3\sqrt{3} + 6 \cdot 4\sqrt{3} + 6 \cdot 5\sqrt{3} \][/tex]

[tex]\[ = 6\sqrt{3} + 24\sqrt{3} + 30\sqrt{3} \][/tex]

[tex]\[ = (6 + 24 + 30)\sqrt{3} = 60\sqrt{3} \][/tex]

So, [tex]\(2 \sqrt{27} + 6 \sqrt{48} + 6 \sqrt{75} = 60 \sqrt{3}.\)[/tex]

Thus, the simplified expressions are:
1. [tex]\(\frac{4 - \sqrt{2}}{2 + \sqrt{2}} = 5 - 3\sqrt{2}\)[/tex]
2. [tex]\(2 \sqrt{2} - 8 \sqrt{32} = -30 \sqrt{2}\)[/tex]
3. [tex]\(2 \sqrt{27} + 6 \sqrt{48} + 6 \sqrt{75} = 60 \sqrt{3}\)[/tex]