Question

Вычислите : а) (3/7+1 3/14)*7; б) (2/9+1 2/3)*3; в) 7/15*2 3/7+7/15*7 4/7; г) 5/12*2 3/7+5/12*3 4/7. Помогите пожалуйста решить ​

Answer 1

а).(6/14 +17/14)×7=6/2 +17/2=23/2=11 1/2 =11,5

б).(2/9 +(5×3)/(3×3))×3=(2/9 +15/9)×3=17/9 ×3=17/3=5 2/3

в).7/15(2 3/7 +7 4/7)=7/15 ×9 7/7=7/15 ×10=7/3 ×2=14/3=4 2/3

г).5/12(2 3/7 +3 4/7)=5/12 ×5 7/7=5/12 ×6=5/2=2 1/2=2,5

Answer 2

а) (3/7+1 3/14)*7 = (6/14 + 3/14)*7 = (9/14)*7 = 3

б) (2/9+1 2/3)*3 = (8/27 + 5/3)*3 = (8/27 + 45/27)*3 = (53/27)*3 = 53/9

в) 7/152 3/7+7/157 4/7 = (14/105 + 21/105)*2 3/7 + (28/105 + 105/105)*7 4/7 = (35/105)*2 3/7 + (133/105)*7 4/7 = (5/15)2 3/7 + (19/15)7 4/7 = 2/32 3/7 + 19/157 4/7 = 4/3 + 44/3 = 48/3 = 16

г) 5/122 3/7+5/123 4/7 = (10/84 + 15/84)*2 3/7 + (20/84 + 30/84)*3 4/7 = (25/84)*2 3/7 + (50/84)*3 4/7 = (25/84)*17/7 + (50/84)*25/7 = 425/588 + 1250/588 = 1675/588 = 675/196

Итак, ответы: а) 3 б) 53/9 в) 16 г) 675/196