4. Simplify:

i. [tex]$5 \sqrt{2} + 7 \sqrt{2} - 4 \sqrt{2}$[/tex]

ii. [tex][tex]$(4 + 3 \sqrt{3})(4 + 4 \sqrt{3})$[/tex][/tex]

iii. [tex]$5 \sqrt{3} - \sqrt{27} - 7 \sqrt{3}$[/tex]



Answer :

Sure, let's simplify each part step by step.

### Part i: Simplify [tex]\(5 \sqrt{2} + 7 \sqrt{2} - 4 \sqrt{2}\)[/tex]

Start by combining the terms with [tex]\(\sqrt{2}\)[/tex]:
[tex]\[ 5 \sqrt{2} + 7 \sqrt{2} - 4 \sqrt{2} = (5 + 7 - 4) \sqrt{2} = 8 \sqrt{2} \][/tex]

The result is:
[tex]\[ 8 \sqrt{2} \approx 11.313708498984763 \][/tex]

### Part ii: Simplify [tex]\((4 + 3 \sqrt{3})(4 + 4 \sqrt{3})\)[/tex]

Use the distributive property (also known as the FOIL method for binomials) to expand the expression:
[tex]\[ (4 + 3 \sqrt{3})(4 + 4 \sqrt{3}) = 4 \cdot 4 + 4 \cdot 4 \sqrt{3} + 3 \sqrt{3} \cdot 4 + 3 \sqrt{3} \cdot 4 \sqrt{3} \][/tex]

Now, calculate each term individually:
[tex]\[ 4 \times 4 = 16 \][/tex]
[tex]\[ 4 \times 4 \sqrt{3} = 16 \sqrt{3} \][/tex]
[tex]\[ 3 \sqrt{3} \times 4 = 12 \sqrt{3} \][/tex]
[tex]\[ 3 \sqrt{3} \times 4 \sqrt{3} = 12 \times 3 = 36 \][/tex]

Combine the terms:
[tex]\[ 16 + 16 \sqrt{3} + 12 \sqrt{3} + 36 \][/tex]

Combine the like terms:
[tex]\[ 16 + 36 + (16+12) \sqrt{3} = 52 + 28 \sqrt{3} \][/tex]

The result is:
[tex]\[ 52 + 28 \sqrt{3} \approx 80.08587988004845 \][/tex]

### Part iii: Simplify [tex]\(5 \sqrt{3} - \sqrt{27} - 7 \sqrt{3}\)[/tex]

First, simplify [tex]\(\sqrt{27}\)[/tex]:
[tex]\[ \sqrt{27} = \sqrt{9 \times 3} = \sqrt{9} \times \sqrt{3} = 3 \sqrt{3} \][/tex]

Substitute this back into the expression:
[tex]\[ 5 \sqrt{3} - 3 \sqrt{3} - 7 \sqrt{3} \][/tex]

Combine the terms with [tex]\(\sqrt{3}\)[/tex]:
[tex]\[ (5 - 3 - 7) \sqrt{3} = -5 \sqrt{3} \][/tex]

The result is:
[tex]\[ -5 \sqrt{3} \approx -8.660254037844387 \][/tex]

### Summary of Results:

1. [tex]\(5 \sqrt{2} + 7 \sqrt{2} - 4 \sqrt{2} = 8 \sqrt{2} \approx 11.313708498984763\)[/tex]
2. [tex]\((4 + 3 \sqrt{3})(4 + 4 \sqrt{3}) = 52 + 28 \sqrt{3} \approx 80.08587988004845\)[/tex]
3. [tex]\(5 \sqrt{3} - \sqrt{27} - 7 \sqrt{3} = -5 \sqrt{3} \approx -8.660254037844387\)[/tex]