Question

Solve the following system of equations by substitution and select the correct answer below:

2x − 4y = 24
4x − 12y = 36


x = 18, y = 3

x = 18, y = −3

x = −18, y = 3

x = −18, y = −3

Answer 1

x=(24+4y)/2

4(24+4y)/2-12y=36
48+8y-12y=36
4y=12
y=3

2x-4x3=24
2x=36
x=18

Correct answer: A

Answer 2

Answer: x = 18, y = 3

Explanation:

Given system of liner equation is :-

`2x-4y=24.....(1)\\4x-12y=36..........(2)`

From (1), we get

`2x=24+4y\\\Rightarrow x=12+2y`.........(3)

Substitute the value of x in equation (2), we get

`4(12+2y)-12y=36\\\Rightarrow\ 48+8y-12y=36\\\Rightarrow-4y=36-48\\\Rightarrow\ -4y=-12\\\Rightarrow\ y=3`

Now, substitute the value of y in (3), we get

`x=12+2(3)=12+6=18`

x = 18, y = 3