Page 110 - Start Up Mathematics_7

Some NCERT Textbook Questions

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1. (a) What should be added to x + xy + y to obtain 2x + 3xy?
(b) What should be subtracted from 2a + 8b + 10 to get –3a + 7b + 16?
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2. What should be taken away from 3x – 4y + 5xy + 20 to obtain –x – y + 6xy + 20?
3. (a) From the sum of 3x – y + 11 and –y – 11, subtract 3x – y – 11.
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(b) From the sum of 4 + 3x and 5 – 4x + 2x , subtract the sum of 3x – 5x and –x + 2x + 5.
4. If m = 2, find the value of:
(a) m – 2 (b) 3m – 5 (c) 9 – 5m
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(d) 3m – 2m – 7 (d) 5m – 4
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5. Simplify the expressions and find the value if x is equal to 2.

(a) x + 7 + 4(x – 5) (b) 3(x + 2) + 5x – 7
(c) 6x + 5(x – 2) (d) 4(2x – 1) + 3x + 11

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6. (a) If z = 10, find the value of z – 3(z – 10)
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(b) If p = –10, find the value of p – 2p – 100
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7. What should be the value of a if the value of 2x + x – a equal to 5, when x = 0?
8. Observe the patterns of digits made from line segments of equal length. You will find such
segmented digits on the display of electronic watches or calculators.

(a) … …

6 11 16 21 ... (5n + 1)…

(b) ... ...

4 7 10 13 ... (3n + 1) ...

(c) ... ...

7 12 17 22 ... (5n + 2) ...

Exemplar Problems

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1. Coefficient of x in –9xy z is:
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(a) 9yz (b) –9yz (c) 9y z (d) –9y z
2. –b – 0 is equal to :
(a) –1 × b (b) 1 – b – 0 (c) 0 – (–1) × b (d) –b – 0 – 1
3. Like terms in the expression n(n + 1) + 6(n – 1) are __________ and __________.

4. If we subtract a monomial from a binomial, then answer is at least a binomial. (True/False)
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5. Add p – 7pq – q and –3p – 2pq + 7q .
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