The height of a sunflower being grown for a botany experiment can be modeled with a linear equation with variables y (height in cm) and x (days after measurements started). The line has slope 2.9. Two weeks after measurements started, the height was 49.1 cm. Use the point-slope form of a line to find the equation. How tall was the sunflower at the first measurement?

Question

m = 2.9 point is (14, 49.1)
y - 49.1 = 2.9(x - 14)
y = 2.9x + 8.5

So....was the sunflower 8.5 cm at the first measurement which would be the first day if I substitute 0 in for x, or, would it be 11.4 cm on day 1 because I have to substitute 1 in for x???

Answer 1

x in the problem is defined as "(days after measurements started)"
... so the 1st measurement would be zero days after start

Answer 2

y=2.9x+49.1; x=14
y=89.7