6n+8c-4=0,9n+10c -7=0?

6n + 8c - 4 = 0,
9n + 10c -7 = 0
6n + 8c = 4 --------- eq.1
3n + 4c = 2 ----------- eq.2 (eq.1 ÷ 2)
9n + 10c = 7 ----- eq.3
27 n + 36 c = 18 ---------- eq.4 (eq. 2 × 9)
27 n + 30 c = 21 ---------- eq.5 (eq. 3 × 3)
6 c = – 3
c = – 1/2
9n – 5 = 7
n = 12/9 = 4/3
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6n + 8c - 4 = 0
9n + 10c - 7 = 0

6n + 8c - 4 = 0
6n = -8c + 4
n = (-8c + 4)/6
9n = 9(-8c + 4)/6

9n + 10c - 7 = 0
9n + 10c = 7
9(-8c + 4)/6 + 10c = 7
3(-8c + 4)/2 + 10c = 7
3(-4c + 2) + 10c = 7
-12c + 6 + 10c = 7
-12c + 10c = 7 - 6
-2c = 1
c = 1/-2
c = -1/2 (-0.5)

6n + 8c - 4 = 0
6n + 8(-1/2) = 4
6n + (-4) = 4
6n - 4 = 4
6n = 4 + 4
6n = 8
n = 8/6
n = 4/3

∴ c = -1/2 (-0.5) , n = 4/3

6n + 8c = 4
9n + 10c = 7

- 60n - 80c = - 40
72n + 80c = 56---------ADD

12n = 16
n = 4/3

24/3 + 8c = 4
8c = - 12/3
c = - 12/24
c = - 1/2

n = 4/3 , c = - 1/2

6n + 8c = 4.........eqn.1
9n + 10c = 7.......eqn. 2


multiplyin eqn 1 with 10 and eqn 2 with 8


60n + 80c = 40
72n + 80c = 56

subtracting eqn 1 from eqn 2


72n + 80c = 56
-60n - 80c = -40

12n = 16

n =4/3

substiute value of n in any eqn to get vsalue of c

6n=4-8c
n=(4-8c)/6...........1
9n+10c -7=0..........2
9[(4-8c)/6]+10c-7=0
{3(4-8c)/2+10c-7=0}2
3(4-8c)+20c-14=0
12-24c+20c-14=0
-4c=2
c=-1/2
n=[4-8(-1/2)]/6
n=[4+4]/6
n=4/3
Answer:
c=-1/2
n=4/3

4/6 - 8/6c = n

9(4/6 - 8/6c) + 10c - 7 = 0

6 - 12c + 10c - 7 = 0

-1 -2c = 0

c = -1/2

put c back into the original eqn.

9n - 5 - 7 = 0

9n = 12

n = 4/3