Test Index

WAEC Further Mathematics 2010 Paper

© africaexams.com

Question : 39

Total: 40

Simplify

(1 + 2\sqrt{3})^{2} - (1 - 2\sqrt{3})^{2}

0
$8\sqrt{3}$
13
$2 - 4\sqrt{3}$

Solution:

Concept:

Use algebraic expansion of squared binomials, then subtract.

Explanation:

Expand the first square:

(1 + 2\sqrt{3})^{2} = 1^{2} + 2(1)(2\sqrt{3}) + (2\sqrt{3})^{2}

= 1 + 4\sqrt{3} + 12 = 13 + 4\sqrt{3}

Expand the second square:

(1 - 2\sqrt{3})^{2} = 1^{2} - 2(1)(2\sqrt{3}) + (2\sqrt{3})^{2}

= 1 - 4\sqrt{3} + 12 = 13 - 4\sqrt{3}

Subtract the second expansion from the first:

(13 + 4\sqrt{3}) - (13 - 4\sqrt{3})

= 13 + 4\sqrt{3} - 13 + 4\sqrt{3}

= 8\sqrt{3}

Answer:

B.

8\sqrt{3}

© africaexams.com

Go to Question:

Prev Question

Next Question