Question

Calculați: a) 24 asupra lui 5+ 1,2= b) 1 1 asupra lui 4×(2 asupra lui 15 ) = c) -10 asupra 7÷ 25 asupra 21 = d) 5 asupra 21 ×(-19,63) + 5 asupra 21 ×(-1,37)=​

Answer 1

Răspuns:

a) 24/5 +1,2=24/5+ 12/10=24/5+6/5=30/5=6

b)1(1/4)x(-2/15)=(1x4+1)/4 x (-2/15)=5/4 x (-2/15)=

scot - si simplific 5 cu 15 => -1/2 x 1/3= -1/6

c)-10/7 : 25/21= -10/7 x 21/25= -2 x 3/5 = -6/5

d) 5/21 x(-19,63)+5/21 x (-1,37)=

tr. expresiile

=5/21x(-1963/100)+5/21 x(-137/100)

inmulteste, simplifica expresiile

=-1/21x 1963/20 -1/21x137/20

inmulteste

=-1963/420-137/420

calculeaza diferenta

=-2100/420

=-5

6.

prima zi: 64,25kg

a doua zi: prima+16,5=64,25+16,5=80,75kg

a treia: dublul primelor 2 zile la un loc=> 2x(prima + a doua)=

=2x(64,25+80,75)=2x145=290kg

adunam toate zilele la un loc=>

64,25kg+80,75kg+290kg=435kg

1kg.........................8,35lei

435kg.....................x lei

x=435:8,35= 52,09 lei a incasat fermierul