There are a couple of ways you can solve this. You can write it out like
(K-3)(K-3)(K-3)(K-3)(K-3)(K-3)(K-3)
And pretty much use the foil method
Or you can use the binomial theorem (google it if you dont know)
The solution should be:
(K^7) - 21(k^6) + 189(k^5) - 945(k^4) + 2835(k^3) - 5103(k^2) + 5103k - 2187
Well, it would be 1+3 which is 4. Then 4+5 which is 9. Then 9+7 which is 16 so your final answer would be 16
I can't see the graph but let's use logic
hmm, more than 10 cubic feet of topsoil so the first and 2nd options are wrong
let's ee the costs
3rd option
10*1=10
2*12=24
10+24=34 and 34<50, that is fine
4th option
3*10=30
2*12=24
30+24=54
54>50, nope, that is over cost
answer is 3rd one
the one with 1 cubic yard compost and 12 cubic yard topsoil