Question

求代数式的值已知x=1/3,y=1/4,求代数式x-(x+y)+(x+2y)+……(x+103y)的值

Answer 1

x-(x+y)+(x+2y)+……(x+103y)

=-y+(x+2y)+(x+3y)+……(x+103y)

=(103-2+1)*x+(2+3+……+103-1)*y

=102*x+(105*51-1)*y

=34+1338.5

=1372.5