Question

all the formulas of class 9 maths

Answer 1

Hello !
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Algebraic Formulas: 
1. (a + b)2 = a2 + 2ab + b2

2. (a - b)2 = a2 -2ab + b2

3. (a + b) (a - b) = a2 -b2

4. (x + a)(x + b) = x2 + (a + b) x + ab

5. (x + a)(x - b) = x2 + (a - b) x -ab

6. (x - a)(x + b) = x2 + (b - a) x -ab

7. (x - a)(x - b) = x2 - (a + b) x + ab

8. (a + b)3 = a3 + b3 + 3ab(a + b)

9. (a - b)3 = a3 - b3 - 3ab (a - b)

10. (x + y + z)2 = x2 + y2 + z2 + 2xy +2yz + 2xz

11. (x + y - z)2 = x2 + y2 + z2 + 2xy - 2yz - 2xz

12. (x - y + z)2 = x2 + y2 + z2 - 2xy - 2yz + 2xz

13. (x - y - z)2 = x2 + y2 + z2 - 2xy + 2yz - 2xz

14. x3 + y3 + z3 - 3xyz = (x + y + z)(x2 + y2 + z2 - xy - yz -xz)

15. (x + a) (x + b) (x + c) = x3 + (a + b + c)x2 + (ab + bc + ca)x + abc

16.  x3 + y3 = (x + y) (x2 - xy + y2)

17.  x3 - y3 = (x - y) (x2 + xy + y2)

Geometric Formulas : 

 Rectangle :
 A = l x w L = length w = width P = 2(l + w) 2 
Triangle
 A = 1/2 x b xh b = base h = height P = a + b + c

 Parallelogram
 A = bh
 P = 2 (b + h)  

Circle
A = πr2   r = radius 
C = 2πr

Cylinder
Lateral surface area A = 2πrh
Total surface area = 2πr2+2πrh 
V = πr2h 2 
Sphere
A = 4πr2 V = 4/3 πr³

Cone
Lateral surface area = πrs
Total surface area = πrs+πr2 
V = 1/3 πr²h 

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