solve equation system e5 q16 *

[tamiatha]

solve the system of equations:
x+3y=5
3x-y=5

my solution:
3x-y=5
3x=5+y
3x-5=y

x+3(3x-5)=5
x+9x-(-15)=5
10x-(-15)=5
10x=20
x=2

3(2)-y=5
6-y=5
1-y=0
1=y

answer=(2,1)

am i right?

 

[Mrspi]

Re: solve equation system e5 q16

solve the system of equations:
x+3y=5
3x-y=5

my solution:
3x-y=5
3x=5+y
3x-5=y

x+3(3x-5)=5
x+9x-(-15)=5
10x-(-15)=5
10x=20
x=2

3(2)-y=5
6-y=5
1-y=0
1=y

answer=(2,1)

am i right?

You can check this yourself. If (2, 1) is a solution for the system of equations, then BOTH equations must be true when you substitute 2 for x and 1 for y.

 

[fasteddie65]

Re: solve equation system e5 q16

solve the system of equations:
x+3y=5
3x-y=5

my solution:
3x-y=5
3x=5+y
3x-5=y

x+3(3x-5)=5
x+9x-(-15)=5 <---- Why do you write -(-15) here? It's just -15.
10x-(-15)=5 <----- 10x - 15 = 5
10x=20 Somehow, you get the right answer.
x=2

3(2)-y=5
6-y=5
1-y=0
1=y

answer=(2,1)

am i right?

You are right, but you are careless with you signs.