Answer:

Step-by-step explanation:
In rectangle ABCD, AB = 6, BC = 8, and DE = DF.
ΔDEF is one-fourth the area of rectangle ABCD.
We want to determine the length of EF.
First, we can find the area of the rectangle. Since the length AB and width BC measures 6 by 8, the area of the rectangle is:

The area of the triangle is 1/4 of this. Therefore:

The area of a triangle is half of its base times its height. The base and height of the triangle is DE and DF. Therefore:

Since DE = DF:

Thus:

Since ABCD is a rectangle, ∠D is a right angle. Then by the Pythagorean Theorem:

Therefore:

Square:

Add:

And finally, we can take the square root of both sides:

5 because if you multiply the previous value by 5, you get the next answer
m = -1
Step-by-step explanation:
-16m = 7 + 9
-16m = 16
m = 16 ÷ -16
m = -1
Answer
Ali has 103 cookies
Step-by-step explanation:
6 x 16 = 96 96 + 7 = 103
Since you are solving for a, you want to have a on one side of the equation and the other terms on another side of the equation. It would be easiest to have all the terms with a on the left side of the equation, so that is what we will do.
Subtract 9a from both sides to get a on the left side of the equation.
5 + 5a = -5
Subtract 5 from both sides of the equation to isolate the term with a.
5a = -10
Divide both sides of the equation by 5 to solve for a.
a = -2