HELP!!! Mom at her witts end..Multiple Choice...

1) Select the ordered pair from the choices below that is a solution to the following system of equations:
-3y - 4x = 21
4x - y = 7

A (0, -7)
B (0, 10)
C (-6, 1)
D (7/3, -7)
Please help me.
My sons math teacher quit in the middle of the school year last year. Which left substitutes in and out for the remainder of the year...they were all over the place and if you werent a math wiz then you didnt have a chance. They offered an online course for kids who had trouble and didnt pass (70% which should have been a big red flag in the first place).

The major problem is..a lot of the problems in the "online course" werent even covered in the regular class or were barely grazed over and with different subs all the time they all taught differently and skipped all over the place. So if you fell behind at all..you were DONE!

This course gives you a quiz after each section. You have 3 chances to pass the quiz or you fail the entire course. We are on our 3rd attempt and getting a 70% each time..you need an 80% to pass the course. We are stuck.

Its heartbreaking to see your kid struggle and you cant help them because you yourself dont understand it and theres nothing you can do. There are 10 questions we need help with. ...I am posting the ones that we need help with here...

1) Select the ordered pair from the choices below that is a solution to the following system of equations:
-3y - 4x = 21
4x - y = 7

A (0, -7)
B (0, 10)
C (-6, 1)
D (7/3, -7)

2) Select the ordered pair from the choices below that is a solution to the following system of equations:
3y = 4x + 32
8x - 2y = 16
A (7, 20)
B (-4, 16/3)
C (0, 32/3)
D (-5, 4)

3) Select the ordered pair from the choices below that is a solution to the following system of equations:
2x = -7y - 13
-6x - 5y = -9

A (-10, -1)
B (1/2, -2)
C (11, -5)
D(4, -3)

4) Select the graph from the choices below that is a solution to the following system of equations:
9x + 5y = -1
-7x + 2y = -11

a)Attachment 24570BAttachment 24571c)Attachment 24572D)None of the above

5)

Select the graph from the choices below that is a solution to the following system of equations.
x – y = -1
3x = -2y + 12

A)

http://i236.photobucket.com/albums/f...ales127/5a.gif

B)

http://i236.photobucket.com/albums/f...ales127/5b.gif

C)

http://i236.photobucket.com/albums/f...ales127/5c.gif

D)

http://i236.photobucket.com/albums/f...ales127/5d.gif

6)
6)The graph below shows the solution to which system of equations?

http://i236.photobucket.com/albums/ff303/zales127/6.gif

A) 3x - y = 6; y + 2 = x
B) 3x + y = 6; y + 2 = x
C) 3x - y = 6; y + 2 = -x
D) 3x + y = 6; y + 2 = -x

7)

Which of the following systems of equations has no solution?
A) 4x - 3y = 12; 6y = 8x - 5
B) 2x - 3 = 5y; -10y - 6 = 4x
C) 8x - y = 7; 2y = -16x + 14
D) -3y = x - 2; 2x - 6y = 7

8)

Which of the following systems of equations has infinitely many solutions?
A) 5x - 5y = 11; 10y = 10x - 22
B) 9x - 3 = 6y; 12y - 6 = 18x
C) 4x - 14y = 5; 14y = 8x + 10
D) 5y = -6x + 6; 3x + 15y = 2

9)

Classify the following system of equations:
4x - 5y = 10
3y = 7x + 14

A) Consistent and independent
B) Inconsistent
C) Consistent and dependent

10)

An artist has 30 kg of an alloy that is 45% copper. How many kilograms of a second alloy that is 70% copper should be mixed with the first alloy to get a new alloy that is 60% copper?
A) 45
B) 35
C) 40
D) 50