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12. Algebraic Expressions
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Q11 of 30 Page 242

Simplify the expression and find its value when a=5 and b = -3, then 2(a2 + ab) +3 - ab

2(a2 + ab) + 3 - ab


= 2a2 + 2ab + 3 -ab


= 2a2 + 2ab - ab + 3


= 2a2+ ab + 3


Put a = 5 and b = -3


=2(5)2 + 5(-3) + 3


=2(25) - 15 + 3


=50 - 12


= 38


More from this chapter

All 30 →
9

If p = -10, find the value of p2 – 2p – 100

10

What should be the value of a if the value of 2x2 + x - a equals to 5, when x = 0?

1

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)


(b)


(c)


If the number of digits formed is taken to be n, the number of segments required to form n digits is given by the algebraic expression appearing on the right of each pattern.


How many segments are required to form 5, 10, 100 digits of the kind

2

Use the given algebraic expression to complete the table of number patterns.



























































































S. No.



Expression



Terms



1st



2nd



3rd



4th



5th



…



10th



…



100th



…



(i)



2n-1



1



3



5



7



9



-



19



-



-



(ii)



3n+2



5



8



11



14



-



-



-



-



-



(iii)



4n+1



5



9



13



17



-



-



-



-



-



(iv)



7n+20



27



34



41



48



-



-



-



-



-



(v)



n2+1



2



5



10



17



-



-



-



-



10001







Questions · 30
12. Algebraic Expressions
1 2 2 3 4 4 5 6 7 1 2 3 4 4 5 6 6 1 2 3 4 5 6 7 8 9 10 11 1 2
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