An equation was used to predict possible sales of phones for 6 months. the actual sales of phones are also listed.

actual sales
55 150 325 510 780 990

predicted sales
40 150 300 500 800 1,000

the sum of the residuals is

Answer with Step-by-step explanation:

Residual is calculated by the difference between actual value and the predicted value.

Actual sales       Predicted sales          Residual

55                        40                                15

150                       150                               0

325                      300                             25

510                       500                             10

780                       800                            -20

990                        1000                           -10

Sum of residuals=15+0+25+10-20-10

                           =20

Hence, sum of residuals is:

20

the answer is (-4,-4)

hope this ! : d