Question

2,3,5 va roggg mult repedee!!!!!

Answer 1

2.
100%-10%=90%
258.75:90%=258.75 ×100/90=287,5 lei

100%+25%=125%
287,5:125%=287,5 ×100/125=230 lei pret initial

3.
a=gaini
b=iepuri
a+b=20       b=20-a
2a+4b=70  
a+2b=35  
a+2(20-a)=35  
a+40-2a=35    
a=5 gaini  
b=15 iepuri

E(x,y)=x²+y²+10x-6y+35 =(x²+10x+25)+(y²-6y+9)+1 =
=(x+5)²+(y-3)²+1 
pentru minim expresie 
(x+5)²=0   x+5=0  x=-5
(y-3)²=0    y-3=0   y=3
E(-5,3)=1