Question

(a+b) (a-b)= (a)²- (b)²​

Answer 1

$\sf \pink{(a+b) (a-b)}$

• Rule: If the first & second is same and the symbol is different ig. +,- then it will remains -..

So we will get $\sf \pink{(a)^2 \ - (b)^2}$

$\bf\color{magenta}{---------------}$

Some more identities:-

$\sf \blue{(x-y)^2=x^2-2xy+y^2}$

$\bf\color{magenta}{---------------}$

$\sf \blue{(x+y)^2=x^2+2xy+y^2}$

$\bf\color{magenta}{---------------}$

$\sf \blue{x^2-y^2=(x-y) (x+y)}$

$\bf\color{magenta}{---------------}$

$\sf \blue{(x+a) (x+b)=x+(a+b)x+ab}$

$\bf\color{magenta}{---------------}$

$\sf \blue{(x+y+z)^2=x^2+y^2+z^2+2xy+2yz+2zx}$

$\bf\color{magenta}{---------------}$

$\sf \blue{(x+y)^3=x^3+y^3+3xy(x+y)}$ $\bf\color{magenta}{---------------}$

$\sf \blue{(x-y)^3=x^3-y^3-3xy(x-y)}$

$\bf\color{magenta}{---------------}$

$\sf \blue{x^3+y^3+x^3-3xyz=(x+y+z)(x^2+y^2+z^2-xy-yz-zx)}$

$\bf\color{magenta}{---------------}$

$\sf \blue{(x+a) (x+b)=x^2+(a+b)x+ab}$

$\bf\color{magenta}{---------------}$