Предмет: Математика, автор: moana12

Помогите пожалуйста!!!
а) -1.8 х + 2.5 = 0.7х +10
в) 0.8(х - 2) - 0.7(х - 1) = 2.7

Решить уравнением:
Кусок железа и кусок меди весят вместе 1044 г , причем вес железа в 1.4 раза больше меди. Сколько весит каждый кусок?

Ответы

Автор ответа: tatianagri2013
0
-1,8х-0,7х=10-2,5
-2,5х=7,5
  х=7,5:(-2,5)
  х= - 3
-1,8*(-3)-0,7*(-3)=5,4+2,1=7,5

0,8х-1,6-0,7х+0,7=2,7
0,1х-0,9=2,7
0,1х=2,7+0,9
0,1х=3,6
х=3,6:0,1
х=36
0,8(36-2)-0,7(36-1)=0,8*34-0,7*35=27,2-24,5=2,7

х-медь
1,4х-железо
х+1,4х=1044
2,4х=1044
х=1044:2,4
х=435
435г-медь
435*1,4=609г железо
435+609=1044г
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