Answer:
1) True 2) True 3) False 4) True
Step-by-step explanation:
In this question let's verify those options
1.Triangle A B C is inside triangle D E F. (true)
If A, B and C are midpoints of DEF then connecting those midpoints we have an interior triangle.
2. Point A is the midpoint of side F D, point B is the midpoint of side D E, point C is the midpoint of side F E. (true)
3. Angles D F E and A B C are right angles. (false)
These triangles are similar. And In this case, the right angles are:

D and C are opposed to the larger side, and not F, and B
Because:
4. The length of D E is 10 centimeters, the length of F D is 6 centimeters, and the length of F E is 8 centimeters. (true)
Let's test this by the Pythagorean Theorem. For DE is the hypotenuse and FD and FE is their legs.

Answer:
x^2 -7x-18
Step-by-step explanation:
(x-9)(x+2)
FOIL
first x*x = x^2
outer 2x
inner -9x
last -9*2 =-18
Add together
x^2 +2x-9x-18
Combine like terms
x^2 -7x-18
Answer:
16 and -4
Step-by-step explanation:
Let the 2 numbers be x and y with x > y
x+y=12
x-y=20
Adding the 2 equations, term by term on both sides, will eliminate y leaving an equation in x that we can solve
(x+x)+(-y+y)=(12+20)
2x=32
x=16
16+y=12
y=-4
16+-4=12
12=12
16--4=20
20=20
Answer:
2x + 5y
———————
x + 4y
Step-by-step explanation: