Система 5z-7x=3 3z+7x=2

Question

Система
5z-7x=3
3z+7x=2

Answer 1

5z-7x=3
3z+7x=2

8z = 5
z = 5/8
z = 0.625

3.125 - 7x = 3
-7x = 3- 3.125
-7x = -0.125
x = 0.125/7

(0.125/7 ; 0.625)

Answer 2

5z-7x=3
3z+7x=2
сложим и получим:
8z=5
z=5/8
3*5/8+7x=2
15/8+7x=2
7x=1/8
x=1/56