CBSE > Class 08 > Mathematics | CBSE Board | Homework Help

1.(x+a)(x+b)=x²+x(a+b)+ab 2.(a+b)²=a²+b²+2ab 3.(a-b)²=a²+b²-2ab 4.a²-b²=(a+b)(a-b) 5.(a+b)³=a³+b³+3ab(a+b) 6.(a-b)³=a³-b³-3ab(a-b) 7.a³+b³=(a+b)³-3ab(a+b) or (a+b)(a²-ab+b²) 8.a³-b³=(a-b)³+3ab(a-b) or (a-b)(a²+ab+b²)

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A what rate%CI per annum will Rs 3209 amount to Rs 3872 in 2 yrs

Posted by Tarun Kumar 7 years, 1 month ago

CBSE > Class 08 > Mathematics

1 answers

Mohit Vishwakarma 7 years, 1 month ago

Amount=3872 Principal =3209 Time=2year Amount=P(1+r/100)^2 3875=3209(1+r/100)^2

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Marks for getting a rank in top 25 in IMO level two in zone

Posted by Alok Singh 7 years, 1 month ago

CBSE > Class 08 > Mathematics

0 answers

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Find the value of the letter in each of the following . 4A+48=CB3

Posted by Harsha Rajappa 7 years, 1 month ago

CBSE > Class 08 > Mathematics

1 answers

Alok Singh 7 years, 1 month ago

It's given 4A + 48 =CB3 A=5 , B = 9, C = 0. 48 + any no. in 40s can never be a 3 digit no.

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What's wrong in this: (a+b)³ = (a+b)(a²+ab+b²)

Posted by Alok Singh 5 years, 11 months ago

CBSE > Class 08 > Mathematics

2 answers

Alok Singh 7 years, 1 month ago

It's (a+b)³=(a+b)(a²-ab+b²)

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Anjali Kumari 7 years, 1 month ago

(a+b)×(a+b)×(a+b)=(a+b)(a×a.+2ab+b×b).

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Two regular polygon are such that the ratio between the number of sides is 1 : 2 and the ratio of measure of their interior angle is 3 :4 find the no.of sides of each polygon

Posted by Anjali Kumari 7 years, 1 month ago

CBSE > Class 08 > Mathematics

4 answers

Anjali Kumari 7 years, 1 month ago

But couldn't we get any formula

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Alok Singh 7 years, 1 month ago

I used trial and error method by using the formula given in the answer , first by reading the question we can understand that one no. of sides double the other as their ratio is 1:2 or x:2x.. Then I tried with 3 n 6, then 4 n 8 and I satisfied the condition by 5 and 10 no. of sides.

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Anjali Kumari 7 years, 1 month ago

But please tell me how to get no.of sides

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Alok Singh 7 years, 1 month ago

Ratio of no. of side=1:2 that means one no. is double the another. Our no. of sides are 5 and 10. For checking : Measure of each angle of a regular pentagon = (n-2)*180/n = (5-2)*180/5= 108. Measure of each angle of a regular decagon =(10-2)*180/10=144. 108/144 = 3:4...

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5-5+5\5*5 67

Posted by Bhavesh Nehte 7 years, 1 month ago

CBSE > Class 08 > Mathematics

2 answers

Amrit Kaur 7 years, 1 month ago

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Raj Kumar 7 years, 1 month ago

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In rational number how to indicate rational numbers on a number line

Posted by Arabinda Kalita 7 years, 1 month ago

CBSE > Class 08 > Mathematics

0 answers

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X+(5x-7)+(-3x+6)

Posted by Prince Kumar 7 years, 1 month ago

CBSE > Class 08 > Mathematics

1 answers

Anjali Kumari 7 years, 1 month ago

(5x+x-3x)+(-7+6) =9x-1

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Factorise=ax+bx-ay-by

Posted by Arshpreet Saini 7 years, 1 month ago

CBSE > Class 08 > Mathematics

1 answers

Harleen Kaur 7 years, 1 month ago

(x-y) (a+b)

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A pipe can fill a cistern in 9 hours due to leak in its bottom the Christian fills up in 10 hours if the custern is full in how much time will it be imptied by the leak

Posted by Sonuhardware Mehandia 7 years, 1 month ago

CBSE > Class 08 > Mathematics

2 answers

Raju Chhabra 7 years, 1 month ago

A pipe can fill cistern in 9 houts B empty it in10hours Work done by pipe A in one hours=1/9 B empty it in one hour=1/10 To empty the tank in how much time=1/9+1/10=19/90=1/5 Time taken to complete awork=total work both done /part of work done 1/1/5=5hours

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Anjali Kumari 7 years, 1 month ago

Incomplete

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Suneeta types 1080 words in one hour what is her GWAM (gross words a minute rate)

Posted by Ashree Akankhya Lenka 7 years, 1 month ago

CBSE > Class 08 > Mathematics

3 answers

Ashree Akankhya Lenka 7 years, 1 month ago

In one hour there is 60 minutes There fore 1080/60=18 So, we concluded that she types 18 word in GWAM

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Harshit Choudhary 7 years, 1 month ago

1080/60=18

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Anjali Kumari 7 years, 1 month ago

1080/60=18

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10percentage of what number is 40?

Posted by Anish Singh 7 years, 1 month ago

CBSE > Class 08 > Mathematics

3 answers

Raju Chhabra 7 years, 1 month ago

10%of x=40 10/100×x=40 x=(40×100)/10 x=40

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Gaurav Seth 7 years, 1 month ago

We have, 10% × x = 40
or, 10/100 × x = 40
Multiplying both sides by 100 and dividing both sides by 10,
we have x = 40 × 100/10
x = 400
If you are using a calculator, simply enter 40×100÷10, which will give you the answer.