Question

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2/3x+ y- 7= 0

4/3x+4y=7/3

m+n/3= 5

3m+n/2= 20- m/3

Answer 1

2/3x + y - 7 = 0 /*3

4/3x + 4y = 7/3 /* 3



2x + 3y - 21 = 0

4x + 12y = 7 /:4



2x + 3y = 21

x + 3y = 7/4



2x + 3y = 21

x = 7/4 - 3y



2(7/4 - 3y) + 3y = 21

x = 7/4 - 3y



7/2 - 6 y + 3y = 21

x = 7/4 - 3y



-3y = 21 - 3 1/2

x = 7/4 - 3y



-3y = 35/2 /:-3

x = 7/4 - 3y



y = -35/2 * 1/3

x = 7/4 - 3y



y = -35/6

x = 7/4 - 3* -35/6



y = -5 5/6

x = 7/4 + 35/2



y = -5 5/6

x = 7/4 + 70/4



y = -5 5/6

x = 77/4 = 19 1/4