cu tot cu calcule lanaga!!
Răspunsuri la întrebare
Răspuns:
Explicație pas cu pas:
5)
a) 3,5·100= 350 ( pur și simplu muți virgula cu doua cifre în dreapta)
5,6·2,7=56/10·27/10=378/25=15,12
4,7·0,69=47/10·69/100=3243/1000=3,243
b) 8,5+12,5·0,6=85/10+125/10·6/10=85/10+15/2=17/2+15/2=32/2=16
c) 6,2+4(18,53-4·3,24)=
62/10+4(1853/100-4·324/100)=
62/10+4(1853-1296/100)=
62/10+4·557/100=
62/10+557/25=
31/5+557/25= (amplificam 31/5 cu 5)
155+557/25=
712/25=
28,48
d)2·(15,6-0,36-1,44)=
2(156/10-36/100-144/100)=
2(78/5-180/100)=
2(78/5-9/5)=
2(78-9/5)=
2·69/5=
138/5=
27,6
7) a+b=3,08=308/100=77/2=>a=77/2-b
b+c=0,55=55/100=11/20=>c=11/20-b
=>3a+7b+4c=?
3·77/2-b+7b+4·11/20-b=
=>3·77/2-b+7b+4·11/20-b=0
=>231/2-b+7b+11/5-b=0
=>1177/10+5b=0
=>5b=-1177/10
=>b=-1177/50
a=77/2-b=>a=77/2+1177/50=>a=1551/25
c=11/20+1177/50=>c=2409/100
=>3a+7b+4c=3·1551/25-7·1177/50+4·2409/100
=>4653/25-8239/50+2409/25
=1177/10