tolong bantu saya gimana cara mengerjakannya

3x - 2y = 7      (x1)
12,5x + y = 7   (x2)
--------------------------
3x - 2y = 7
25x + 2y = 14
----------------------+
28x = 21
x = 21/28
x = 3/4

3x - 2y = 7
3 (3/4) - 2y =7
9/4 - 2y = 7
2y = 9/4 - 7
2y = 9/4 - 28/4
2y = -19/4
y = -19/4 : 2
y = -19/8

10x + 15y = 10(3/4) + 15(-19/8) = 30/4 - 285/8 = 90/8 - 285/8 = -195/8 = 24 3/8