model.lm2 <- lm(df$SalesPrice ~ df$SqFeet + df$Garage + df$Year + df$Quality + df$Style + df$Lot)
summary(model.lm2)

Coefficients:
              Estimate Std. Error t value Pr(>|t|)
(Intercept) -2680.9219   397.1155  -6.751 4.04e-11 ***
df$SqFeet     105.8539     6.8433  15.468  < 2e-16 ***
df$Garage       9.6069     4.9504   1.941  0.05286 .
df$Year         1.4262     0.2011   7.092 4.50e-12 ***
df$Quality2  -133.4846    10.4911 -12.724  < 2e-16 ***
df$Quality3  -149.4913    13.9734 -10.698  < 2e-16 ***
df$Style2     -25.2898     9.0856  -2.784  0.00558 **
df$Style3     -13.4706     8.7225  -1.544  0.12313
df$Style4      11.6082    18.0938   0.642  0.52145
df$Style5     -26.8263    14.8151  -1.811  0.07077 .
df$Style6      -4.6575    14.9504  -0.312  0.75553
df$Style7     -40.5276     8.5626  -4.733 2.88e-06 ***
df$Lot          1.2919     0.2312   5.589 3.75e-08 ***