What is - 9 + 3 = I know its -6 but how

Timed*** there are 8 rows and 8 columns, or 64 squares on a chessboard. suppose you place 1 penny on row 1 column a, 2 pennies on row 1 column b, 4 pennies on row 1 column c, and so on … how many pennies are on each square? a =   b =   c = d =   e =   f = g =   h =

1mile equals approximately 1.6 kilometers. which best approximates the number of miles in 6 kilometers?

Write two point-slope equations for the line passing through the points (6, 5) and (3, 1)