Question

Вычислите рациональным способом.
1.(0.9 ·5 +5 *0.6) - (0.7*2+3 *0.7)
2.(13*2.5-2.5 * 9)+ ( 8* 5.6 -3.1*8)
3.(3.61*7+7*0.13)-(2.26*4+3*2.26)
Пожалуйста помогите.

Answer 1

1.(0.9 ·5 +5 *0.6) - (0.7*2+3 *0.7)=5(0.9+0.6)+0.7(2+3)=5*1.5+0.7*5=7.5+3.5=11

2.(13*2.5-2.5 * 9)+ ( 8* 5.6 -3.1*8)=2.5(13-9)+8(5.6-3.1)=2.5*4+8*2.5=2.5(4+8)=2.5*12=30

3.(3.61*7+7*0.13)-(2.26*4+3*2.26)=7(3.61+0.13)-2.26(4+3)=7*3.74-2.26*7=7(3.74-2.26)=7*1.48=10.36