Quick help? Will fan + medal?

Solve, using linear combination.

3x + y = 4
2x + y = 5

(–1, 7)
(0, 4)
(–3, 12)
(–3, 13)

How many solutions are there to the following system of equations?

2x + 5y = –11
10x + 25y = –55

0
1
2
infinitely many

How many solutions are there to the following system of equations?

3x + 7y = –10
15x + 35y = –45

0
1
2
infinitely many

Question

Quick help? Will fan + medal?

Solve, using linear combination.

3x + y = 4
2x + y = 5

       (–1, 7)
       (0, 4)
       (–3, 12)
       (–3, 13)

How many solutions are there to the following system of equations?

2x + 5y = –11
10x + 25y = –55


       0
       1
       2
       infinitely many

How many solutions are there to the following system of equations?

3x + 7y = –10
15x + 35y = –45


       0
       1
       2
       infinitely many

anonymous · Answer

$$3x + y = 4\ 2x + y = 5 $$ subtract the second equation from the first and get 
$$x=-1$$