Answer:
First one
Step-by-step explanation:
Variable b is 7 more than variable c:
b = c + 7
Variable b is also 1 less than variable c:
b = c - 1
Answer:
0.25
Step-by-step explanation:
Average means 
According to the formula, each student in Mr. Goldwasser's class read

books on average, and each student in Mr. Welch's class read

books on average.
Therefore, the answer will be

Answer:
15ft
Step-by-step explanation:
Answer:p = (2100 - x)/25
Step-by-step explanation:
According to the law of demand, when the price,p of the brand of MP3 players is is high, the quantity,x of the brand of MP3 players demanded would be low and when the price,p of the brand of MP3 players is is low, the quantity,x of the brand of MP3 players demanded would be high.
To derive the demand equation, we would apply the slope intercept form of equation which is expressed as
y = mx + c
Where
m = slope
c = intercept
The slope, m would be
(y2 - y1)/(x2 - x1)
Slope = (1100 - 100)/(40 - 80) = 1000/-40
Slope = - 25
To find the y intercept, we would substitute m = - 25, y = 1100 and x = 40 into y = mx + c. It becomes
1100 = - 25 × 40 + c
1100 = - 1000 + c
c = 1100 + 1000 = 2100
y = - 25x + 2100
Therefore, the demand equation is
x = - 25p + 2100
25p = 2100 - x
p = (2100 - x)/25