metode eliminasi tolong bantu dengan benar

langsung jawab
8.
* 8x = 55
x = 55/8
* 5x - 8y = 15
5(55/8) - 8y = 15
275/8 - 8y = 15
-8y = 15 - 275/8
-8y = -155/8
y = 155/64
{55/8 , 155/64}

9.
* -b = 15
b = -15
* -4a - 3b = 3
-4a - 3(-15) = 3
a = 21/2
{21/2 , -15}

10.
11c + 2d = 17
5c + 2d = 19
> kalikan kedua ruas dengan -1

11c + 2d =37
-5c - 2d =-19
* 6c = 18
c = 3
* 5c + 2d = 19
5(3) + 2d = 19
15 + 2d = 19
2d = 19-15
2d = 4
d= 2
{3, 2}

11.
2e - 5f = 1
4e - 5f = 5
> kalikan kedua ruas dengan -1

2e-5f=1
-4e+5f=-5
* -2e = -4
e = 2
* 2e - 5f = 1
2(2) - 5f = 1
4 - 5f = 1
5f = 1-4
5f = -3
f = 3/5
{2, 3/5}

cuman segitu yg bisa saya jawab....