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Exercise 12.2

Questions in Exercise 12.2

BOOKS

1. NCERT Solutions - Mathematics, Class 7

CHAPTERS

1. Integers

2. Fractions and Decimals

3. Data Handling

4. Simple Equations

5. Lines and Angles

6. The Triangle and its properties

7. Congruence of Triangles

8. Comparing Quantities

9. Rational Numbers

10. Perimeter and Area

11. Algebraic Expressions

12. Exponents and Powers

13. Symmetry

14. Visualising Solid Shapes

EXERCISES

Q1) Simplify combining like terms:

i) $21b-32+7b-20b$

ii) $-z^2+13z^2-5z+7z^3-15z$

iii) $p-(p-q)-q-(q-p)$

iv) $3a-2b-ab-(a-b+ab)+3ab+b-a$

v) $5x^2y-5x^2+3yx^2-3y^2+x^2-y^2+8xy^2-3y^2$

vi) $(3y2+5y-4)-(8y-y2-4)$

Q2) Add:

i) $3mn,-5mn,8mn,-4mn$

ii) $t-8tz,3tz-z,z-t$

iii) $-7mn+5,12mn+2,9mn-8,-2mn-3$

iv) $a+b-3,b-a+3,a-b+3$

v) $14x+10y-12xy-13,18-7x-10y+8xy,4xy$

vi) $5m-7n,3n-4m+2,2m-3mn-5$

vii) $4x^2y,-3xy^2,-5xy^2,5x^2y$

viii) $3p^2q^2-4pq+5,-10p^2q^2,15+9pq+7p^2q^2$

ix) $ab-4a,4b-ab,4a-4b$

x) $x^2-y^2-1,y^2-1-x^2,1-x^2-y^2$

Q3) Subtract

i) $-5y^2\ from\ y^2$

ii) $6xy\ from-12xy$

iii) $(a-b)\ from\ (a+b)$

iv) $a(b-5)\ from\ b(5-a)$

v) $-m^2+5mn\ from\ 4m^2-3mn+8$

vi) $-x^2+10x-5\ from\ 5x-10$

vii) $5a^2-7ab+5b^{2\ }from\ 3ab-2a^2-2b^2$

viii) $4pq-5q^2-3p^2\ from\ 5p^2+3q^2-pq$

Q4) (a) What should be added to $x^2+xy+y^2$ to obtain $2x^2+3xy$ ?

(b) What should be subtracted from $2a+8b+10$ to get $-3a+7b+16$

Q5) What should be taken away from $3x^2-4y^2+5xy+20$ to obtain $-x^2-y^2+6xy+20$ ?

Q6) (a) From the sum of $3x-y+11$ and $-y-11$ subtract $3x-y-11$ .

(b) From the sum of $4+3x$ and $5-4x+2x^2$ subtract the sum of $3x^2-5x$ and $-x^2+2x+5$ .

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Questions in Exercise 12.2

Q1) Simplify combining like terms:

i) $21b-32+7b-20b$

ii) $-z^2+13z^2-5z+7z^3-15z$

iii) $p-(p-q)-q-(q-p)$

iv) $3a-2b-ab-(a-b+ab)+3ab+b-a$

v) $5x^2y-5x^2+3yx^2-3y^2+x^2-y^2+8xy^2-3y^2$

vi) $(3y2+5y-4)-(8y-y2-4)$

Q2) Add:

i) $3mn,-5mn,8mn,-4mn$

ii) $t-8tz,3tz-z,z-t$

iii) $-7mn+5,12mn+2,9mn-8,-2mn-3$

iv) $a+b-3,b-a+3,a-b+3$

v) $14x+10y-12xy-13,18-7x-10y+8xy,4xy$

vi) $5m-7n,3n-4m+2,2m-3mn-5$

vii) $4x^2y,-3xy^2,-5xy^2,5x^2y$

viii) $3p^2q^2-4pq+5,-10p^2q^2,15+9pq+7p^2q^2$

ix) $ab-4a,4b-ab,4a-4b$

x) $x^2-y^2-1,y^2-1-x^2,1-x^2-y^2$

Q3) Subtract

i) $-5y^2\ from\ y^2$

ii) $6xy\ from-12xy$

iii) $(a-b)\ from\ (a+b)$

iv) $a(b-5)\ from\ b(5-a)$

v) $-m^2+5mn\ from\ 4m^2-3mn+8$

vi) $-x^2+10x-5\ from\ 5x-10$

vii) $5a^2-7ab+5b^{2\ }from\ 3ab-2a^2-2b^2$

viii) $4pq-5q^2-3p^2\ from\ 5p^2+3q^2-pq$

Q4) (a) What should be added to $x^2+xy+y^2$ to obtain $2x^2+3xy$ ?

(b) What should be subtracted from $2a+8b+10$ to get $-3a+7b+16$

Q5) What should be taken away from $3x^2-4y^2+5xy+20$ to obtain $-x^2-y^2+6xy+20$ ?

Q6) (a) From the sum of $3x-y+11$ and $-y-11$ subtract $3x-y-11$ .

(b) From the sum of $4+3x$ and $5-4x+2x^2$ subtract the sum of $3x^2-5x$ and $-x^2+2x+5$ .

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Learn from an expert tutor.

Book a free class now

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