 # Some Useful Algebra Formulas

Algebra Formulas are very important for mathematics as well as science. If you are an aspirant of competitive exams like SSC, CGL, Rail NTPC, Police, Defence, etc. then you should remember all the formulas. Remembering formula is not going to help to crack any examinations, one should have the ability to execute these formulas in the exam hall. To do so one has to practice the various types of algebraic math problems.

```Contents
Square Formula
Cube Formula
Laws of Exponent
Irrational number Formula```
Also if you are a student of class 7, class 8, class 9 or class 10, then you definitely remember these formulas of Algebra.

## Some Important Formulas of Algebra

### Square Formula

(x+y)= (x+y)(x+y) = x2+2xy+y2

(x-y)= (x-y)(x-y) = x2-2xy+y2

(x+y)= (x-y)2 + 4xy

(x-y)= (x+y)2 – 4xy

x2-y2 = (x+y)(x+y)

(x + y + z)2 = x2 + y2 + z2 + 2xy + 2xz + 2yx

4xy = [ (x+y)2 – (x-y)2 ]

2( x2+y2) = [ (x+y)2 + (x-y)2 ]

### Cube Formula

(x + y)3 = x3 + 3x2y + 3xy2 + y3

(x + y)3 = x3 + y3 + 3xy(x + y)

(x – y)3 = x3 – 3x2y + 3xy2 – y3

(x – y)3 = x3 – y3 – 3xy(x – y)

x3 + y3 = (x + y)(y2 – xy + y2)

x3 – y3 = (x – y)(x2 + xy + y2)

(x + y)4 = x4 + 4x3y + 6x2y2 + 4xy3 + y4)

(x – y)4 = x4 – 4x3y + 6x2y2 – 4xy3 + y4)

x4 – y4 = (x2 + y2)(x + y) (x – y)

x3 + y3 + z3 – 3xyz = (x + y + z)( x2 + y2 + z2 -xy – yz – zx)

### Laws of Exponent

xm × xn = xm+n

xm / xn = xm-n

(xy)m = xm × ym

(xm)n = xmn

xm = (1/x-m)

x0 = 1

√x = x½

³√x = x¹/³ 