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3. (a) Simplify $$\sqrt{50} - \sqrt{18}$$ giving your answer in the form $a\sqrt{2}$, where $a$ is an integer - Edexcel - A-Level Maths Pure - Question 5 - 2016 - Paper 1

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3.-(a)-Simplify--$$\sqrt{50}---\sqrt{18}$$-giving-your-answer-in-the-form-$a\sqrt{2}$,-where-$a$-is-an-integer-Edexcel-A-Level Maths Pure-Question 5-2016-Paper 1.png

3. (a) Simplify $$\sqrt{50} - \sqrt{18}$$ giving your answer in the form $a\sqrt{2}$, where $a$ is an integer. (b) Hence, or otherwise, simplify $$\frac{12\sqrt{3... show full transcript

Worked Solution & Example Answer:3. (a) Simplify $$\sqrt{50} - \sqrt{18}$$ giving your answer in the form $a\sqrt{2}$, where $a$ is an integer - Edexcel - A-Level Maths Pure - Question 5 - 2016 - Paper 1

Step 1

Simplify $\sqrt{50} - \sqrt{18}$

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Answer

To simplify the expression, we first break down the square roots:

  1. Calculate 50\sqrt{50}: 50=252=52\sqrt{50} = \sqrt{25 \cdot 2} = 5\sqrt{2}

  2. Calculate 18\sqrt{18}: 18=92=32\sqrt{18} = \sqrt{9 \cdot 2} = 3\sqrt{2}

  3. Now substitute these values back into the expression: 5232=(53)2=225\sqrt{2} - 3\sqrt{2} = (5 - 3)\sqrt{2} = 2\sqrt{2}

Thus, the simplified form is 222\sqrt{2}.

Step 2

Hence, or otherwise, simplify $\frac{12\sqrt{3}}{\sqrt{50} - \sqrt{18}}$

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Answer

Using the result from part (a):

  1. Substitute 5018\sqrt{50} - \sqrt{18} with 222\sqrt{2}: 12322\frac{12\sqrt{3}}{2\sqrt{2}}

  2. Simplify the fraction: =12232=632= \frac{12}{2} \cdot \frac{\sqrt{3}}{\sqrt{2}} = 6 \cdot \frac{\sqrt{3}}{\sqrt{2}} =632= 6 \cdot \sqrt{\frac{3}{2}}

Thus, writing in the form bcb\sqrt{c}, we have: 6326\sqrt{\frac{3}{2}} or equivalently, with integer values for bb and cc, we can write: =63/2= 6\sqrt{3}/\sqrt{2}

Finally, we rationalize the denominator, multiplying numerator and denominator by 2\sqrt{2}: =662=36= \frac{6\sqrt{6}}{2} = 3\sqrt{6}

So the final answer in the required form is 363\sqrt{6}.

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