If we know your Pythagorean Triples we can immediately recognize that the last choice is a right triangle:
8² + 15² = 17²
If you don't know your Pythagorean Triples, it's worth learning the first few off the list because teachers use them in problems all the time. But for now let's just exhaustively check the Pythagorean Theorem for each triangle. We don't have to multiply everything out; we can analyze the common factors. If two have a common factor that the third one doesn't have, there's no way for the Pythagorean Theorem to add up.
Clearly 5²+15² is a multiple of 5 but 18² isn't so that one isn't a right triangle.
6²+12² is a multiple of 6, 16² isn't a multiple of 6, not an RT.
15²-5² is a multiple of 5, 13² isn't, no joy.
8²+15² = 64 + 225 = 289 = 17² -- that's a real right triangle, a valid Pythagorean Triple.
Answer: The mass of the object is 10 kg
Step-by-step explanation:
According to Newton's second law of motion, the force 
applied to an object with mass 
is directly proportional to its acceleration 
:
(1)
If we isolate :
(2) This means the acceleration of the object varies inversely with its mass
Now, we are given the following data to calculate a constant force using (1):
(3)
(4)
(5)
If we apply this same force calulated in (4) in another object with an acceleration of 
, its mass 
will be:
(6)
(7)
Finding :
This is the mass of the object
By distributing the 4 onto the 5x and the 6, you would end up with 20x + 24.
M+f=35
f=5+m^2
sub 5+m^2 for f
m+5+m^2=35
m^2+m+5=35
minus 35 both sides
m^2+m-30=0
factor
what 2 numbers mulitply to get -30 and add to get 1
-5 and 6
(m-5)(m+6)=0
set to zto
m-5=0
m=5
m+6=0
m=-6
age can't be negative
max is 5
father is 30
