<u><em>Answer</em></u>

<u><em>Explanation</em></u>
Based on the given conditions, formulate:: 
Substitute
into
:: 
Rearrange variables to the left side of the equation: 
Calculate the sum or difference: 
Divide both sides of the equation by the coefficient of variable: 
Cross out the common factor: 
Answer:
n = 21
Step-by-step explanation:
Given
n + 19 = 40 ( subtract 19 from both sides )
n = 40 - 19 = 21
Answer:
4 yards long
Step-by-step explanation:
John's garden is 12 ft long and 3 ft go into a yard. With this information you then divide 12 by 3 to see how many yards would go into the 12. 12/3=4
Answer: (0, -3/7)
Step-by-step explanation:
The Y-intercept would be the value of y when x is at 0, which is when the Y axis is intercepted. -3/7 is the starting position of the function when the the X = 0.