If m + n = 7 and 2n - 3m = 6, what is the value of 3n - 2m?

Since m + n = 7 we know m = 7-n. So now we have 2n - 3 (7-n) = 6. From this we get n = - 3. So now we know m - 3 = 7 so m = 10. So now we have 3 (-3) + 2 (10) = ? and this comes out as 11

m + n = 7 then m = 7 - n

2n - 3m = 6

substitute m = 7 - n into 2n - 3m = 6

2n - 3m = 6

2n - 3 (7 - n) = 6

2n - 21 + 3n = 6

5n - 21 = 6

5n = 27

n = 27/5

n = 5.4

m + n = 7

m = 7 - n

m = 7 - 5.4

m = 1.6

now you have m = 1.6 and n = 5.4

you can find the value of 3n - 2m

3n - 2m

=3 (5.4) - 2 (1.6)

= 16.2 - 3.2

= 13