The rate at which a plant grows is constant. At the 3rd week it is 12 inches tall and at the 5th week it is 20 inches tall. If this information is plotted on a coordinate plane, what is the y-coordinate of the point (1, y)?

Question

Responses
A 11
B 22
C 44
D 9

Answer 1

D 9

To find the y-coordinate at x=1, we can use the formula for a linear relationship: y = mx + b.

First, we find the slope (m) using the two given points:
m = (y2 - y1) / (x2 - x1)
m = (20 - 12) / (5-3) = 8/2 = 4

Now that we have the slope, we can calculate the y-intercept (b) by using one of the points (let's use (3, 12)):
12 = 4(3) + b
12 = 12 + b
b = 0

Now we have the equation for the relationship between x and y:
y = 4x

When x = 1, y = 4(1) = 4, so the y-coordinate of the point (1, y) is 4. In this case, option D (9) is incorrect. The correct answer is 4.