Okay so im taking this online test and i have no idea what to do, i think i am right so far though but i don;'t know what to do next

z1=3+4i

z2=(-4-7i

z3=-6+3i

To solve:

z1*(z2+z3)

so far ive done the right side because im pretty sure you have to do that side first and im at...

3+4*[(-4-7i)+(6+3i)]

-10-4i^2

-10-4(-1)

-10+4

-6

so am i doing this right, if im not then can someone please help me out? lol, with work shown thanks a lot!=]