Vector operation 7 (a + b) - 8 (a-b) Where a and B are vectors, and the simplified formula

Vector operation 7 (a + b) - 8 (a-b) Where a and B are vectors, and the simplified formula


It's the same as the ordinary formula
-a+15b



How to square the sum of vector a and B


a=(m,n)
b=(x,y)
a+b=(m+x,n+y)
(a+b)^2=(a+b)(a+b)=(m+x,n+y)(m+x,n+y)=(m+x)^2+(n+y)^2
=m^2+x^2+n^2+y^2+2mx+2ny



How to square the vector a


Is equal to the square of the vector a module