CBSE > Class 09 > Mathematics | CBSE Board | Homework Help

We know that

(a+b+c)² = a² + b² + c² + 2(ab + bc + ca)

So,

(-2x + 5y - 3z)²

= (-2x)² + (5y)² + (-3z)² + 2 [ (-2x)*5y + 5y*(-3z) + (-3z)*(-2x) ]

= 4x² + 25y² + 9z² + 2 [ (-10xy) + (-15yz) + 6xz ]

= 4x² + 25y² + 9z² - 20xy - 30yz + 12xz

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ANSWER

The vulgar fraction of 2.91919191919191 is

Posted by Ridhima Agrawal 4 years, 2 months ago

CBSE > Class 09 > Mathematics

1 answers

Rajiv Barman 4 years, 2 months ago

2.91 bar

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ANSWER

If x=-2 and y=-1 then find the value of mx+2y=15

Posted by Sunil Nitnaware 4 years, 2 months ago

CBSE > Class 09 > Mathematics

3 answers

Divya Gupta 4 years, 2 months ago

M=15/-3

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Sunisha Flower Decoretion 4 years, 2 months ago

Given, x=-2 and y=-1 Then, mx+2y =15 m×-2+2×-1=15 -2m +(-2) =15 -2m -2 =15 -2m =15+2 -2m =17 -m =17÷2 -m = 8.5 m = -8.5

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Sunil Nitnaware 4 years, 2 months ago

M= 15/4

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ANSWER

Find five rational numbers between 3/5and 4/5

Posted by Ridhima Agrawal 4 years, 2 months ago

CBSE > Class 09 > Mathematics

1 answers

Gaurav Seth 4 years, 2 months ago

Find five rational numbers between 3/5 and 4/5.
Solution: Since we want five numbers, we write 3/5 and 4/5 So multiply in numerator and denominator by 5+1 =6 we get

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ANSWER

x+y+z is neither a monomial nor a ___________

Posted by Rohith Jutla 4 years, 2 months ago

CBSE > Class 09 > Mathematics

1 answers

Arihant Sharma 4 years, 2 months ago

Trinomial

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ANSWER

rational number between 1 to 2

Posted by Akshay Garg 4 years, 2 months ago

CBSE > Class 09 > Mathematics

2 answers

Akshay Garg 4 years, 2 months ago

0Thank You

Ridhima Agrawal 4 years, 2 months ago

How many numbers we have to find

2Thank You

ANSWER

What is the coffecient of x cube in 2x + x square - 6 x cube

Posted by Hamid Khan 4 years, 2 months ago

CBSE > Class 09 > Mathematics

2 answers

Aman Yadav 4 years, 2 months ago

-6 is the coefficient of x^3

1Thank You

Bhavya Singh 4 years, 2 months ago

-6....... according to me

2Thank You

ANSWER

Decimal expansion of the number √2 is a.A finite decimal b.1.41421 c.Non-terminating recurring d. Non-terminating non recurring

Posted by Suzanne Smitha 4 years, 2 months ago

CBSE > Class 09 > Mathematics

3 answers

Kartavya Khandelwal 4 years, 2 months ago

Non terminating non recurring (d)

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Suzanne Smitha 4 years, 2 months ago

Thanks

0Thank You

Yogita Ingle 4 years, 2 months ago

√2 is non terminating non repeating because root 2 is an irrational number

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ANSWER

Find the value of a³+8b³ if a+2b = 10 and ab = 15

Posted by Trishla Jain 4 years, 2 months ago

CBSE > Class 09 > Mathematics

1 answers

Yogita Ingle 4 years, 2 months ago

Given: a+2b=10 and ab=15
Consider, a³+8b³ = a³ + (2b³)
=(a + 2b)³ - 3 × a × 2b(a + 2b) {SInce, a³ + b³ =(a + b )- 3ab(a + b)}
=(a + 2b)³ - 6ab(a + 2ab)
=(10)³- 6 × 15 × 10
=1000- 900 =100

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ANSWER

Factorise : 8x³ - 27y³ + 125z³ + 90xyz

Posted by Trishla Jain 4 years, 2 months ago

CBSE > Class 09 > Mathematics

1 answers

Yogita Ingle 4 years, 2 months ago

8x³−27y³+125z³+ 90xyz
Using,
a³+b³+c³−3abc=(a+b+c)(a²+b²+c²−ab−bc−ca)
Here,
a=2x
b=−3y
c=5z,
Therefore,
=>(2x)³+(−3y)³+(5z)³−3×2x×(−3y)×5z
=(2x−3y+5z)(4x²+9y²+25z²+6xy+15yz−10xz)

2Thank You

ANSWER

Find the value of (2.7)³ - (1.6)³ - (1.1)³ using a suitable identity

Posted by Trishla Jain 4 years, 2 months ago

CBSE > Class 09 > Mathematics

1 answers

Yogita Ingle 4 years, 2 months ago

{tex}2.7^3-1.6^3{/tex}

{tex}=(2.7-1.6)^3+3(2.7)(1.6)(2.7-1.6){/tex}

{tex}=(1.1)^3+3(2.7)(1.6)(1.1){/tex}

{tex}=(1.1)^3+14.256{/tex}

{tex}2.7^3-1.6^3-1.1^3{/tex}

{tex}=(1.1)^3+14.256-(1.1)^3{/tex}

{tex}=14.256{/tex}

1Thank You

ANSWER

What is root of 24

Posted by Vedant Bhadra 4 years, 2 months ago

CBSE > Class 09 > Mathematics

2 answers

Astha Bhagat 4 years, 2 months ago

Search on google or in calculator

0Thank You

Vedant Bhadra 4 years, 2 months ago

Thx

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ANSWER

7x-9=16

Posted by Rekha Rani 4 years, 2 months ago

CBSE > Class 09 > Mathematics

2 answers

Priyanshu Bisht 4 years, 2 months ago

7x=16+9,7x=25/7answer is 25 by 7

1Thank You

Bhairav Lomte 4 years, 2 months ago

Man can I get the question paper of polynomials only

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ANSWER

1BY 2+ROOT 3

Posted by Priyanshu Bisht 4 years, 2 months ago

CBSE > Class 09 > Mathematics

2 answers

Priyanshu Bisht 4 years, 2 months ago

0Thank You

Silviya Shrivastav 4 years, 2 months ago

√3=1.73 1/2+1.73 1/2+173/100 Take LCM:100 50/100+173/100 =2.23

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ANSWER

A classroom is 7m long, 6.5m wide and 4m high. It has one door 3m × 1.4m and three windows each measuring 2m × 1m. The interior wall is to be colour washed, find the cost of colour washing at the rate of ₹3.5 per m².

Posted by K Kaviya 4 years, 2 months ago

CBSE > Class 09 > Mathematics

1 answers

Gaurav Seth 4 years, 2 months ago

l = 7m, n = 6.5m and h = 4m

∴ Area of the room = 2( l + b)h = 2(7 + 6.5) 4 = 108m²

Area of door = 3 × 1.4 = 4.2m²

Area of one window = 3 × 2 = 6m²

∴ Area of 3 windows = 3 × 2 = 6m²

∴ Area of the walls of the room to be colour washed = 108 - (4.2 + 6)

= 108 - 10.2 = 97.8m²

∴ Cost of colour washing @ Rs. 3.5 per square metre = 97.8 × 3.5 = Rs. 342.3

1Thank You

ANSWER

The floor of a rectangular field has a perimeter of 250m and it's length and breadth are in the ratio 13:12. If the cost of painting the four walls and ceiling at the rate of ₹5m² is ₹27000, find the height of the hall.

Posted by K Kaviya 4 years, 2 months ago

CBSE > Class 09 > Mathematics

1 answers

Silviya Shrivastav 4 years, 2 months ago

Area=27000/5 =5400m² Perimeter=2(l+b) 250 =2(12x+13x) 250= 2(25x) 250 =50x 250/50=x = 5 Now, 12x=60 13x=65 CSA=2(l+b)*h(area of four side) 5400m² =2(60+65)*h 5400. =250*h 5400/250=h=21.6

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ANSWER

P(x)= 3x+1;x =-1/3

Posted by Sonali Prajapat 4 years, 2 months ago

CBSE > Class 09 > Mathematics

3 answers

Divya Gupta 4 years, 2 months ago

P(x)=3(-1/3)+1 P(x)= -1+1 =0

0Thank You

Ananya Jaiswal 4 years, 2 months ago

P(x)=3x+1 If x=-1/3 Then, 3x+1=3(-1/3)+1 =-1+1=0 Hope this would help ??

0Thank You

Ashvin Kharadi 4 years, 2 months ago

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ANSWER

The surface area if a cuboid is 1372 cm². If it's diameter are in the ratio 4:2:1, find its length ?

Posted by K Kaviya 4 years, 2 months ago

CBSE > Class 09 > Mathematics

1 answers

Ananya Jaiswal 4 years, 2 months ago

Let the dimensions be=4x,2x & x Surface area of cuboid =2(lb+bh+hl) 1372=2(4x*2x+2x*x+4x*x) 1372=2(8x²+2x²+4x²) 1372=2(14x²) 1372/2=14x² 686=14x² 686/14=x² 49=x² √49=x 7=x Hence x=7 Therefore, length=4x=4*7=28 Hope this would help ??

1Thank You

ANSWER

The edge of a cube is 10.5mm. Find the find the total surface area in cmsquare.

Posted by K Kaviya 4 years, 2 months ago

CBSE > Class 09 > Mathematics

1 answers

Gaurav Seth 4 years, 2 months ago

Given:

edge of cube = 10.5mm

Find :

total surface area in cm^2

Solution :

total surface area of cube = 6 a^2

area = 6 ×10.5^2

= 6×110.25 cm^2

= 661.5 cm^2

1Thank You

ANSWER

The edge of a cube is 10.5mm. Find the find the total surface area in cmsquare.

Posted by K Kaviya 4 years, 2 months ago

CBSE > Class 09 > Mathematics

1 answers

Yogita Ingle 4 years, 2 months ago

The edge of the cube is 10.5mm = =10.5/10 cm
find its total surface area in cm.
Total surface area of cube =6a² edge
SA=6 ×10.5/10×10.5/10

=6.615 cm².

1Thank You

ANSWER

find the two rational between 5/7 and6/7

Posted by Raghunath Tulo 4 years, 2 months ago

CBSE > Class 09 > Mathematics