There's nothing to solve because it's not equal to anything. You can't solve something like 2x = 6 (x = 3) with the = part.
As for graphing, if you want to do that by hand it will be a lot of work. You'll need to computer a lot of numbers to get something that looks like what the graph actually looks like. As a 6th degree equation it can have up to 5 humps (like how a 2nd degree equation, a parabola, has 1 hump), so it's going to be a challenge to graph by hand.
If you want to see the graph without charting it yourself, just type plot(x^6+4x^5-3x^4-28x^3-46x^2-72x-72) into Google.