The expression n2 + n represents the total number of blocks used in the nth figure of a pattern. Use the equation n2 + n = 56 to determine which figure has 56 blocks.

This is an equation that is quadratic in form. so to solve th given equation we must first factor it:

n2 + n = 56n2 + n - 56 = 0 (n - 7) (n + 8) = 0equate to zeron - 7 = 0n = 7andn + 8 = 0n = - 8

so the 7th figure has 56 blocks because there are no negative nth figure