Question

proof of X +y whole square

Answer 1

(x+y)^2= (x+y)(x+y)

x(x+y)+y(x+y)

x^2+xy+xy+y^2

x^2 + 2xy+ y^2

Answer 2

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