Fred is conducting a controlled experiment to test whether using a grow light at night will help a tomato plant grow faster. Below are the steps to Fred's experiment: Plant tomato plants in two separate, but identical, flowerpots.

Place the flowerpots in the same area outside during the day.

At night, bring both flower pots inside and place one in the dark and one under a grow light.

Give the plants the same amount of food and water each week.

Measure the growth of the plants.

Draw conclusions based on the data collected.

Which of the following variables must Fred hold constant in this experiment?
A.
the amount of time both plants spend in the dark
B.
the type of tomato plants used
C.
the length of time this experiment is carried out
D.
the amount of time both plants spend in the light

m a t h w a y. c o m

step-by-step explanation:

b. 153 students do not participate in sports and seventy-five 12th graders were surveyed

step-by-step explanation:

part a. the differences are decreasing, so we know the sequence is not arithmetic. the ratios are constant (=3/4), so we know the sequence is geometric.

part b. from part a, we know the common ratio is 3/4, so each term is 3/4 of the one before. the initial term is the number of gallons at h=1.

g[h] = (3/4)·g[h-1]

g[1] = 384 . . . . initial value required for a recursive definition

part c. the general formula for a geometric sequence is

a[n] = a[1]·r^(n-1)

we have a[1] = 384, r = 3/4, and the term number given by h. the formula that follows is

g[h] = 384·(3/4)^(h-1)

part d. filling in the value and doing the arithmetic, we have

g[12] = 384·(3/4)^11 ≈ 384·0.042235136 ≈ 16.2183 . . gallons

part e. each gallon is 4 quarts, so

16.2183 gal × 4 qt/gal = 64.8732 qt

given the equation is 8+9z=-6, the first step would be to subtract the 8 from both sides:

8+9z-8=-6-8

since 8 minus 8 = 0, this would cancel out the 8. and since -6 minus 8 equals -14, the equation would look like this

9z = -14