lesson 15-1 practice

Question

Write an equation to represent Travis and Roy traveling from the farm to the distribution plant in Dallas

Time hours distance miles

2 230

2.5 200

3 170

3.5 140

A y=-60x+350

B y=60x−350

C y=60x +350

D y=-60-350

Answer 1

Looking at the time and distance numbers from your chart, if you were to plot these points with x being TIME and y being the distance, you will notice that the line will slant downward and it has a NEGATIVE slope.

For the sake of my solution here, I'm organizing the ordered points as such:

P₁ (2, 230)

P₂ (2.5, 200)

P₃ (3, 170)

P₄ (3.5, 140)

You can use the POINT-SLOPE Equation but you need to calculate the slope and pick ONE point to use for x₁ & y₁

y - y₁ = m (x - x₁)

You can use ANY two points, the slope will be the SAME

where m = y₂ - y₁ / (x₂ - x₁) = (200 - 230)/(2.5 - 2) = -30/0.5 = -60

y - 230 = -60(x - 2)

y - 230 = -60x -(60)(-2)

y - 230 = -60x +120

y = -60x +120 +230

y = -60x +350 Final Answer...based on values given the chart.

Hope this helps..