Найдите корни уравнений (х-16)*5=420 (16+х)*20=680

5(x-16)=420                  20(16+x)=680
5x-80=420                        320+20x=680
5x=500                               20x=360
x=100                                x=18

(х-16)* 5 =420
х - 16 =420 : 5
х-16=84
х=84+16
х=100


(16 +х) * 20=680
16 + х=680 : 20
16 +х=34
х=34 - 16
х=18