If 2x+6y = 12 and y= 3x+5, find the values of x and y.

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justaguide's profile pic

justaguide | College Teacher | (Level 2) Distinguished Educator

Posted on

The equations to be solved for x and y are:

2x + 6y = 12 ...(1)

y = 3x + 5 ...(2)

Substitute y = 3x + 5 in (1)

=> 2x + 6(3x + 5) = 12

=> 2x + 18x + 30 = 12

=> 20x = -18

=> x = -18/20

=> -0.9

y = 3*(-0.9) + 5

=> y = 2.3

The solution of the system of equations is x = -0.9 and y = 2.3

hala718's profile pic

hala718 | High School Teacher | (Level 1) Educator Emeritus

Posted on

Given the system of equations:

2x + 6y = 12..............(1)

y= 3x + 5 .............(2)

We need to find the solution to the system.

We will use the substitution method to solve.

We will substitute (2) into (1)

==> 2x + 6( 3x+5) = 12

==> 2x + 18x + 30 = 12

==> 20x = 12- 30

==> 20x = -18

==> x = -18/20 = -9/10

Now we will substitute into (2) to find y.

==> y= 3x +5 = 3*-9/10 + 5 = (-27 + 50)/10 = 23/10

Then the answer is : x= -9/10  and y= 23/10

nothing111's profile pic

nothing111 | Student | eNotes Newbie

Posted on

use subsitution

2x+6(3x+5)+12

2x+18x+30=12

20x=-18

x=0.9

y=3(0.9)+5

=7.7

Hope that is correct

 

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