Linear Equation: Find Line Through (0,9) with Domain x < 8

Question

Choose the equation that represents a straight line that is positive in the domain 8 > x

and passes through the point (0,9) (0,9) .

Video Solution

Step-by-Step Solution

To solve this problem, we'll identify the correct equation of a line that passes through the point (0,9) (0, 9) and remains positive when x<8 x < 8 .

  • Step 1: Identify the y-intercept using the given point (0,9) (0, 9) . The y-intercept c c is 9, leading to a partial equation: y=mx+9 y = mx + 9 .
  • Step 2: Determine the appropriate slope m m so that the line is positive for x<8 x < 8 . This means the line should decrease (positive to the right implies negative to the left) as x x decreases from 8, requiring a negative slope.
  • Step 3: Given the provided choices, y=118x+9 y = -1\frac{1}{8}x + 9 matches these requirements because it incorporates:
    • The correct y-intercept at 9.
    • The negative slope, ensuring y y is positive for x<8 x < 8 .

The correct line equation that fulfills these conditions is therefore y=118x+9 y = -1\frac{1}{8}x + 9 .

Answer

y=118x+9 y=-1\frac{1}{8}x+9