Answer:
  y = 380
Explanation:
Pick any two points in table to find slope, let's use (4, 350) and (6, 330):
 m = (y₂ - y₁) / (x₂ - x₁)
 = (330 - 350) / (6 - 4)
 = -20 / 2
 m = -10
Pick any one point in table, let's use (4, 350) and slope m from above to find y-intercept:
 y = mx + b
 350 = -10(4) + b
 350 = -40 + b
 b = 390
Use m and b from above to form Equation of line:
 y = mx + b
  y = -10x + 390
Pick a few points from table to check equation y = -10x + 390 is valid:
 Point (4, 350) 
 350 = -10(4) + 390
 350 = -40 + 390
 350 = 350
 Point (8, 310) 
 310 = -10(8) + 390
 310 = -80 + 390
 310 = 310
What is y when x = 1:
 y = -10x + 390
 y = -10(1) + 390
 y = -10 + 390
  y = 380