1. Solve the system by using a table. 3y=4x+7 , -4x-4y=28. These are the possible solutions: A) (–4, –3), B) (–3, –4), C) (4, 3)
, D) (3, 4).
2.Solve by graphing. -3x-y=-10, 4x-4y=8. possible solutions: A) (-1,3), B) (3-1), C) (1,3), D) (3,1)
3. The spreadsheet shows the monthly revenue and expenses for a new business.Use the models to predict the month in which revenue will equal expenses. Possible answers:
A) October
B) September
C) August
D) May
2.Solve by graphing. -3x-y=-10, 4x-4y=8. possible solutions: A) (-1,3), B) (3-1), C) (1,3), D) (3,1)
3. The spreadsheet shows the monthly revenue and expenses for a new business.Use the models to predict the month in which revenue will equal expenses. Possible answers:
A) October
B) September
C) August
D) May
2 answers:
<span>The first question:
3y=4x+7 (1)
-4x-4y=28 (2)
Let's plug in x = -4, -3, 3, and 4 and see the y-values :)
I have attached the table since it's hard to make a table with text :P
As you can see, when x = -4, that is when the y-values are equal. That means that is the solution to the system of equations. Your answer is A) (-4, -3).
The second question:
</span><span>-3x-y=-10 (1)
4x-4y=8 (2)
</span>
When you graph both equations, you will see that they intersect at D) (3, 1).
The third question:
We need to find the lines for revenues and expenses.
To find the line for revenues, make months the x-value and revenues the y-values. And find the equation. You should get y = 4,100x + 300.
To find the line for expenses, make months the x-value and expenses the y-values. And find the equation. You should get y = 1,900x + 19,990.
Now graph both solutions and see where they intersect. They intersect at approximately (8.95, 36995)
That would be during the month of C) August.
3y=4x+7 (1)
-4x-4y=28 (2)
Let's plug in x = -4, -3, 3, and 4 and see the y-values :)
I have attached the table since it's hard to make a table with text :P
As you can see, when x = -4, that is when the y-values are equal. That means that is the solution to the system of equations. Your answer is A) (-4, -3).
The second question:
</span><span>-3x-y=-10 (1)
4x-4y=8 (2)
</span>
When you graph both equations, you will see that they intersect at D) (3, 1).
The third question:
We need to find the lines for revenues and expenses.
To find the line for revenues, make months the x-value and revenues the y-values. And find the equation. You should get y = 4,100x + 300.
To find the line for expenses, make months the x-value and expenses the y-values. And find the equation. You should get y = 1,900x + 19,990.
Now graph both solutions and see where they intersect. They intersect at approximately (8.95, 36995)
That would be during the month of C) August.
Answer:
1) (A) (-4,-3)
2) (D) (3,1)
3) (B) September
Step-by-step explanation:
1) 4x+7=3y
-4x-4y=28
By elimination method, we get y= -3 and x= -4
Hence (A)(-4,-3) is correct.
2) We will pot the points for the equations -3-y= -10 and 4x-4y = 8
The point of intersection is the solution that is (D) (3,1).
3) We can solve it by assuming revenue - expenses, and for revenue= expenses
We need to prove difference = 0
Let x denotes the month and y denotes the difference between revenue and expenses.
Then for January = (1,18000)
Feb = (2,15000)
march = (3,12000)
April = (4,11000)
may = (5,9000) and so on
The best fit line for the points is y= -2200x+19,600
We need y= 0
Then, x = 19,600/2200
= 8.9 = 9 (approx)
In 9th month (September) the difference will be 0 and revenue = expenses.
(B) is correct.
You might be interested in