8×(х-3)=4×(х+7)

8х-24=4х+28

8х-4х-24=28

4х-24=28

4х=28+24

4х=52

х=52÷4

х=13

8 ( х - 3 ) = 4 ( х + 7 )

8х - 8 * 3 = 4х + 4 * 7

8х - 24 = 4х + 28

8х - 4х = 28 + 24

4х = 28 + 24

4х = 52

х = 52 : 4

х = 13

проверка:

8 * ( 13 - 3 ) = 4 * ( 13 + 7 )

8 * 10 = 4 * 20

80 = 80