Answer:

Step-by-step explanation:
we know that
A relationship between two variables, x, and y, represent a direct variation if it can be expressed in the form
or 
In this problem
Let
x------> the number of gallons
y------> the number of miles
the relationship between the number of miles and the gallons of gas represent a linear direct variation
The constant of proportionality k is equal to the slope m

therefore
the equation of the linear equation

Answer:
7 years
Step-by-step explanation:
Given that:
Let Richard's age = x
Elder sister's age = 2x
Youngwr sister's age = x - 2
Product of sisters ages = 70
2x * (x - 2) = 70
2x² - 4x = 70
2x² - 4x - 70 = 0
x² - 2x - 35 = 0
x² - 7x + 5x - 35 = 0
x(x - 7) +5(x - 7) = 0
(x - 7) or (x + 5) = 0
x = 7 or x = - 5
X can't be negative
Hence, x = 7
Richard is 7 years
Answer: the slope would be -4/3 and the y intercept is 2
Step-by-step explanation: you would have to divide both sides by 3 to get y by itself. that leaves you with -4/3x + 2
Answer:
a) x-4+9
b) x-2
For part b, I am not 100% sure about my answer, but I am sure about part a.