Answer:
EF = 20 cm
Step-by-step explanation:
Here, we want to find the length of EF
To do this, we use the principle of similar triangles
The similar triangles we are considering here will be ;
FEA and FBD
when two triangles are similar, the ratio of their corresponding sides are equal
Let us calculate DC first
we can use Pythagoras’ theorem here and it is that the square of the hypotenuse equals the sum of the square of the two other sides
Using the triangle EDC
15^2 = 12^2 + DC^2
DC^2 = 225-144
DC^2 = 81
DC = 9
So the entire length of BD is 9 + 12 = 21 cm
Thus, we have it that;
Let EF be x
so DF = 15 + x
Hence;
BD/DF = AE/EF
21/15+x = 12/x
21x = 12(15 + x)
21x = 180 + 12x
21x-12x = 180
9x = 180
x = 180/9
x = 20 cm
EF = 20 cm
With no limiting factors to the growth of the plants, the number of months have passed since the plants were first introduced is 23.1.
<h3>What is an exponential function?</h3>
Exponential function is the function in which the function growth or decay with the power of the independent variable. The curve of the exponential function depends on the value of its variable.
A type of plant is introduced into an ecosystem and quickly begins to take over.
A scientist counts the number of plants after m months and develops the equation to model the situation, which is given as,

Most recently, the scientist counted 138 plants.

Taking log both sides of the equation,

Thus, with no limiting factors to the growth of the plants, the number of months have passed since the plants were first introduced is 23.1.
Learn more about the exponential function here;
brainly.com/question/15602982
For the first part:Every shirt she grabs, will cost her dollars, so if she grabs 3 shirts, then the cost of the shirts is:

With the same rationale, if she grabs 2 pairs of jeans, the cost of the jeans is:

So, her total is:

If you subtract 3 from the total, then the expression is:
For the second part:If she's paying 3 less for each shirt, then the cost of 3 shirts will become:

In the same fashion, for the two jeans:

So the expression for the total cost is:
For number three:The amounts are different because the cost of the total purchase is different than the cost of each element that makes up the total purchase.
For number four:If you're the owner, you want to give the smallest amount of discount (the one in part 1/a).
So you could clarify by saying there's 3 dollars of the TOTAL purchase's cost.
Answer:
false
Step-by-step explanation: