Question

What is the solution to the system of equations that contains –3x + y = 3 and 2x – y = –1?

A. no solution
B. (–1, 3)
C. infinite number of solutions
D. (–2, –3

Answer 1

add them together

–3x + y = 3
2x – y = –1
----------
-x = 2

Answer 2

thanks but just to make sure the answer is b right

Answer 3

how do you get conclusion it's b ?

Answer 4

well I see –3x + y = 3 2x – y = –1 and the last numbers for both those equations are the same #'s as B

Answer 5

I believe the ( , ) states values that x and y must take

in our case, we found x = -2 and there was no constraint for y
there are probably infinitely many solutions

Answer 6

you can look at it this way -> no matter what we choose for y:
the second equation always cancels the first one

Answer 7

oh :) ok thanks

Answer 8

you're welcome ;)

Answer 9

The answer ended up being D

Answer 10

thanks for the feedback

Answer 11

haha no problem

Answer 12

–3(-2) + y = 3
6 + y = 3
y = 3-6
y=-3

2(-2) – y = –1
-4 -y = -1
-4 = y -1
-3 = y

Answer 13

I believe there are infinitely many solutions if you get

0=0

in case you run into a problem like that in the future

Answer 14

-3x + y = 3
2x - y = -1
-----------
-x = 2
x = -2

now sub -2 in for x in either of the equations
2x - y = -1
2(-2) - y = -1
-4 - y = -1
-y = -1 + 4
-y = 3
y = -3

answer is D.