(720-а*6)-200=340? (3*а-20)-600=300? (у:4-39)*12=300? решить

(720 - а × 6) - 200 = 340 720 - 6а = 340 + 200 720 - 6а = 540 6а = 720 - 540 6а = 180 а = 180 ÷ 6 а = 30

(3*a-20)-600=300 3a-20=300+600 3a=900+20 3a=920 a=920/3 a=300 2/3