Answer:
Height of fir tree = 9 meters
height of pine tree= 12 meters
Step-by-step explanation:
The combined height of one fir tree and one pine tree is 21 meters. The height of 4 fir trees stacked on top of each other is 24 meters taller than one pine tree.
Let x be the height of fir tree and y be the height of pine tree

Subtract x from both sides

height of 4 fir trees = pine tree +24

Substitute 21-x or y in the above equation

Add x on both sides

Divide by 5 on both sides
x=9
Now plug in 9 for x and find out y


y=12
Height of fir tree = 9 meters
height of pine tree= 12 meters
You could do subtract for one because if you are TAKING AWAY the money from her savings account by spending it.
Keyword: TAKING AWAY
Answer: They are parallel
Step-by-step explanation:
If two lines are parallel , then they must have the same slope and if two lines are perpendicular , the product of their slope must be -1.
To check this , we must calculate the slope of the two lines given.
Slope = 
from the first point
= 2
= 1
= 5
= -1
substituting the values
slope 1 = 1 - 2 / -3 - 5
slope1 = -1 / -8
slope 1 = 1/8
Using the same format to calculate the slope of the second line
= -2
= 0
= -1
= 15
slope 2 = 0 - (-2) / 15 - (-1)
slope 2 = 2/16
slope 2 = 1/8
Since slope 1 = slope 2 , this implies that the lines are parallel
The correct answer should be B because it does cross the y-axis at -5 and it does decres from x = -10 till x = -2 and then does remain constant till x=10