Answer:-31 (perhaps if I 100% knew what I was doing, but this is what I believe the answer should look like based on my research which consisted of me finding out the mechanics of such expressions from a website I found online)Step-by-step explanation:I have never had to solve a question like this, so my answer is to be taken with a grain of salt (bucket full).When we see that funky symbol over there, we're going to want to do some funky things:6∑(-2k + 5)k=3So we'll substitute 3 for k, as seen here:(-2(3) + 5)But wait! We still got that 6, so we'll throw that in with the 3:(-2(3 · 6) + 5)From here, we PEMDAS or whatever you prefer until we're done!(-2(18) + 5)(-36 + 5)(-31)-31[Processing ends successfully.. Just kidding, I ain't no robot!]