Answer: x = -3
Step-by-step explanation:
2y + x = -15
y = 2x
2y = 2(2x) = 4x
4x + x = -15
5x = -15
x = -3
Let 
and 
be the number of elves and reindeers, respectively.
We know that:
(so far 14 of them have arrived)
(each reindeer has 4 legs and each elf has two)
If we multiply the first equation by 2 we have 
, and if we subtract this equation from the second we have 
which implies 
.
So, there are 5 reindeers and 9 elves (remember that they have to sum up to 14).
They are parallel to eachother
Answer: Second option: (4,0) and (-9,0)
f(x)=x^2+5x-36
The x-intercepts of the graph of a function f(x) are the values of the variable x that makes f(x)=y equal to zero. To find these values we only have to equal f(x)=y to zero:
f(x)=y=0
x^2+5x-36=0
Factoring the polynomial:
(x+9)(x-4)=0
Using that if a b=0, then: a=0 or b=0
with a=x+9 and b=x-4
x+9=0 or x-4=0
Solving for x:
x+9-9=0-9 or x-4+4=0+4
x=-9 or x=4
Then the x-intercepts are the poitns (x,y)=(x,0):
(4,0) and (-9,0)
