Answer:
x = - 5
Step-by-step explanation:
Given
5x + 7 = 2x - 8 ( subtract 2x from both sides )
3x + 7 = - 8 ( subtract 7 from both sides )
3x = - 15 ( divide both sides by 3 )
x = - 5
3/7 is the answer for this question
The formula for depreciation is:

Where x = Initial value,
y= Amount after depreciation.
r= Rate of depreciation,
t = time (in years)
According to given problem,
x = 1040, y= 944 and t = 12 months =1 year.
So, first step is to plug in these values in the above formula, So,

944 = 1040 (1 -r)
Divide each sides by 1040.
0.907692308 =1 - r
0.907692308 - 1 = -r Subtract 1 from each sides.
-0.092307692 = -r
So, r = 0.09 or 9%.
Now plug in 0.09 in the above equation to get the depreciation equation. So,

So, 
b) To find the value of the bike after 5 months,
plug in t = 5 months= 5/12 = 0.41667 years in the above equation of depreciation.
So, 
y = 1040 * 0.961465659
y = 999.9242852
y = 1000 (Rounded to nearest integer).
Hence, the value of the bike after 5 months is $1000.
Answer:
The teacher can purchase 61 pencils with $5
Step-by-step explanation:
This is a simple proportion problem. It can be solved by pure logic reasoning without any formulas
It a dozen pencils cost $0.97, each pencil cost $0.97/12=0.08083
With $5 she will be able to purchase 5/0.08083=61.85 pencils
We must round to the nearest lower integer
The teacher can purchase 61 pencils with $5