Question

The graph shows the amount of money paid when purchasing bags of peanuts at the zoo:

A graph is shown. The x-axis is labeled from 0 to 9. The y-axis is labeled from 0 to 13. The four points shown on the graph are ordered pairs 0, 0 and 1, 4 and 2, 8 and 3, 12. These points are joined by a line. The label on the x-axis is Bags of peanuts. The title on the y-axis is Total cost in dollars.

Write an equation to represent the relationship between the total cost (y) and the number of bags of peanuts (x).

y = 4x
y = one-fourth x
y = 3x
y = one-third x

Answer 1

long method:

take two points on the graph (let's use (0,0) and (1,4) from the graph) and use the slope formula

(y2-y1) / (x2-x1) to find the slope m

then the equation is simply y = mx + b. since the y intercept is zero, this becomes y = mx

intuitive method:

start with (0,0), notice how the graph goes up 4 units and to the right 1 unit. consider what this means if slope = rise/run

Answer 2

i got it thanks