how to solve a system of diff eq ?

[hpfx]

Hello,
I try to solve this small system of differential equation :

x'(t)+y(t)=t^2
x'(t)+y'(t)=6

with initial conds : x(0)=0 and y(0)=1

I tried with desolve on 10077,
something like that desolve({x'+y=t^2, x'+y'=6} and x(0)=0 and y(0)=1, {x,y})
but I didn't get any result.

does someone knows how to do ?