Question

Urgent va rog!!!!...............

Answer 1

1)

3+[3*(-2-4)+15]+21=3+(3*(-6)+15)+21=3+(-18+15)+21=3+(-3)+21=21

2)

2x+1/13-echiunitara ⇒2x+1=13

2x+1=13

2x=13-1

2x=12

x=6

3)

5 robinete...125 litri

7 robinete...x

x=125*7/5

x=875/5

x=175 litri

4)

AB≡BC⇒ΔABC isoscel

MND-is

AN=AM si MC=NB

AN=AM

MC=NB

BD=DB

⇔ΔMND isoscel

5)

p=pretul initial

pretul dupa scumpire=p+20*p/100=p+p/5=6p/5

pretul dupa ieftinire=6p/5-(6p/5)*20/100=6p/5-(6p/5)*(1/5)=6p/5-6p/25

6p/5-6p/25=168,numitor comun 25

30p-6p=4200

24p=4200

p=4200/24

p=175 lei