Question

Melvin is building a castle with a series of towers out of blocks. Each tower has twice as many blocks as the previous tower, and then 3 more. If the first tower has x^2+2x+3 blocks in it, and Melvin builds 5 towers in all, how many blocks will he have used in total?

Answer 1

x^2+2x+3+2(x^2+2x+3)+3+4(x^2+2x+3)+6+8(x^2+2x+3)+9+16(x^2+2x+3)+12
add that up and you will get your answer and you get 31x²+62x+123