The first one is (v+6)(v-6)
Answer:

Step-by-step explanation:
Subtract the 4 from 9
Answer:
Area: 6a^2
Perimeter: 12a^2
Step-by-step explanation:
To find the area of a triangle, use the formula A=1/2 b*h. The base is 3a^2 and the height is 4a^2.
A= 1/2 (3a^2)(4a^2)
A = 1/2 (12a^4)
A = 6a^4
To find the perimeter of the triangle, add each of the sides of the triangle. The third side, the hypotenuse, can be found using Pythagorean theorem.

Now add each of the sides: 3a^2 + 4a^2 +5a^2 = 12a^2
Answer:
25
Step-by-step explanation:
The median of a trapezoid equals one half of the sum of the bases
AC is a median and EB and DF are the bases.
hence AC = 1/2(EB + DF)
We are given that EB = 13 and that AC = 19. And we need to find DF
To do so we plug in what we are given and solve for DF
AC = 1/2(EB + DF)
AC = 19, EB = 13
19 = 1/2(13 + DF)
Now solve for DF
* Multiply both sides by 2*
19 * 2 = 38
1/2(13 + DF) * 2 ( the 1/2 and 2 cancel out and we're left with 13 + DF )
We then have 38 = 13 + DF
* Subtract 13 from both sides *
38 - 13 = 13 - 13 + DF
We get that DF = 25