Question

System solving2x-4y = 12   
x+3y = 3

Accepted Answer

First, find a value for x using the second equation:
x = 3 - 3y
Then substitute that in to the first equation
2 (3-3y) - 4y = 12
6 - 6y - 4y = 12
- 10y = 6
y = -.6
Then you plug this back into the first equation
x + 3*-.6 = 3
x - 1.8 = 3
x = 4.8
So, x = 4.8 and y = -.6

Answer

You can use substitution to solve the system of equations

2x - 4y = 12 ...(1)
x + 3y = 3 ...(2)
From (2), x + 3y = 3
=> x = 3 - 3y
Substitute this in (1)
2*(3 - 3y) - 4y = 12
=> 6 - 6y - 4y = 12
=> 6 - 10y = 12
=> 10y = -6
=> y = -6/10
x = 3 - 3y = 3 + 3*(6/10) = 3 + 18/10
=> x = 48/10
The solution of the system of equations is x = 48/10 and y = -6/10

Answer

We'll solve the system using elimination method.
We'll multiply the 1st equation by 3:
6x - 12y = 36 (3)
We'll multiply the 2nd equation by 4:
4x + 12y = 12 (4)
We'll add (3) + (4):
6x - 12y + 4x + 12y  = 36 + 12
We'll combine and eliminate like terms:
10x = 48
x = 4.8
We'll substitute x in the 2nd equation:
4.8 + 3y = 3
3y = 3 - 4.8
3y = -1.8
y = -1.8/3
y = -0.6
The solution of the system is the pair (4.8 ; -0.6).

Math

System solving 2x-4y = 12 x+3y = 3

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