А≈2,78 в≈6,90
2,78+6,90=9,68
2,78-6,9=-4,12
2,5х - 6,3 = 7 1/3
2,5х - 6,3 = 22/3
2,5х = 22/3 + 6,3 = 22/3 + 63/10
2,5х = 220/30 +189/30 = 409/30
25/10 х = 409/30
75/30 х = 409/30
х = 409/30 / 75/30 = 409/30 * 30/75 = 409/75 = 5 34/75
х равен 5 34/75 или 5,45