Questions & Answers: "Expansion Formulae and Algebraic Identities"

Complete guide to "Expansion Formulae and Algebraic Identities" for Math students. Below you will find important questions and model answers to help you prepare.

4 Questions

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Question 1

1 Mark

Which of the two alternative expressions from the given are perfect squares?

Options

Option A is correctDiagram for Option A
Option B Diagram for Option B
Option C Diagram for Option C
Option D is correctDiagram for Option D

Question 2

1 Mark

If a2+b2=325a^{2}+b^{2}=325 and a+b=23a+b=23 and ab=102ab=102 Find (ab)(a-b).

Options

Option A

16

Option B

18

Option C

17

Option D is correct

11

Question 3

1 Mark

Which term should be added to 49x2+149x249x^2+\frac{1}{49x^2} to make the expression a complete square. (Choose two correct alternatives.)

Options

Option A is correct

-2

Option B

-14x

Option C is correct

2

Option D

14x

Explanation

To make the expression 49x2+149x249x^2+\frac{1}{49x^2} a complete square, we need to add a term that fits the form (a+b)2=a2+b2+2ab(a+b)^2 = a^2 + b^2 + 2ab or (ab)2=a2+b22ab(a-b)^2 = a^2 + b^2 - 2ab. Here, a2=49x2a^2 = 49x^2, so a=7xa = 7x. And b2=149x2b^2 = \frac{1}{49x^2}, so b=17xb = \frac{1}{7x}. The term to be added is either 2ab2ab or 2ab-2ab. 2ab=2×(7x)×(17x)=22ab = 2 \times (7x) \times (\frac{1}{7x}) = 2. And 2ab=2×(7x)×(17x)=2-2ab = -2 \times (7x) \times (\frac{1}{7x}) = -2. Thus, the terms that can be added are 2 and -2.

Question 4

1 Mark

Find the value of (225)21(15)2+1\frac{(225)^2-1}{(15)^2+1}

Options

Option A is correct

224

Option B

226

Option C

326

Option D

225