What is the solution of the system of linear equations 3x + 18y = 6 and 8x + 2y = 8

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted on

The system of linear equations that has to be solved is

3x + 18y = 6 ...(1)

8x + 2y = 8 ...(2)

(1) - 9*(2)

=> 3x - 72x + 18y - 18y = 6 - 72

=> -69x = -66

=> x = `66/69`

=> x = `22/23`

Substitute in (2)

`2y = 8 - (8*22)/23`

=> `2y = 8/23`

=> `y = 4/23`

The solution of the system of linear equations is x = `22/23 ` and y = `4/23`

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jess1999 | Student, Grade 9 | (Level 1) Valedictorian

Posted on

3x + 18y = 6

8x + 2y = 8

First multiply everything in the second equation by 9

By multiplying, you should get

 3x  + 18y = 6

72x + 18y = 72 now, subtract 18y with 18y ( which means subtract 3x with 72x and 7 with 72 )

By subtracting, you should get

-69x = -66 divide by -69 on both sides

By dividing, you should get

x = 66/69 now simplify

x = 22/23 which is your answer for " x "

Now plug 22/23 into one of the equation

8 (22/23) + 2y = 8 multiply 22/23 with 8

By multiplying, you should get

176/23 + 2y = 8 subtract 176/23 on both sides

By subtracting, you should get

2y = 8/23 divide by 2 on both sides

By dividing, you should get

y = 4/23 which is your answer for " y "

So x = 22/23 ; y = 4/23

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