Is 6.700 equal to 6.7?

Yes because zeros have no value if they are after a decimal and have no number behind them

-x - 2y = -10  |add x to both sides

-2y = x - 10    |divide both sides by (-2)

y = -0.5x + 5

for x = 0, y = -0.5(0) + 5 = 0 + 5 = 5 ⇒ (0; 5)
for x = -2, y = -0.5(-2) + 5 = 1 + 5 = 6 ⇒ (-2; 6)
for x = 2, y= -0.5(2) + 5 = -1 + 5 = 4 ⇒ (2; 4)

The graph in the picture