Question

Simplify and combine like terms...
21b-32+7b-20b​​

Answer 1

Answer:

8b -32

Step-by-step explanation:

21b- 32 + 7b - 20b

= 21b - 20b + 7b - 32

= 8b - 32

Answer 2

Ncert solutions

Grade 7

Mathematics

Science

Chapters in NCERT Solutions - Mathematics, Class 7

Exercises in Algebraic Expressions

Question 1

Q1) Simplify combining like terms:

i) 21b-32+7b-20b21b−32+7b−20b

ii) -z^2+13z^2-5z+7z^3-15z−z

2

+13z

2

−5z+7z

3

−15z

iii) p-(p-q)-q-(q-p)p−(p−q)−q−(q−p)

iv) 3a-2b-ab-(a-b+ab)+3ab+b-a3a−2b−ab−(a−b+ab)+3ab+b−a

v) 5x^2y-5x^2+3yx^2-3y^2+x^2-y^2+8xy^2-3y^25x

2

y−5x

2

+3yx

2

−3y

2

+x

2

−y

2

+8xy

2

−3y

2

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

Solution i) 21b-32+7b-20b21b−32+7b−20b

Now, we re-arrange the like terms which gives us

= 21b\ +\ 7b\ -\ 20b\ -\ 3221b + 7b − 20b − 32

= b\left(21\ +\ 7\ -\ 20\right)\ -\ 32b(21 + 7 − 20) − 32

= 8b\ -\ 328b − 32