Question

Calculati: 
a) (2,5x la a5-a + 0,3x²- 0,8x²):(-x²)

b) Calculati valoarea numarului:

(x-5)²-(x+2)²
supra           +2x
7

c) Rezolvati sistemul:

0,5x+1supra4 y=3
1supra2x-0,25y=1

Answer 1

a)
(2,5x^5  + 0,3x²- 0,8x²):(-x²)
x²(2,5x³+0,3-0,8):(-x²)
(0,5-2,5x³)=0,5(1-5x³)
b)
(x²-10x+25-x²-4x-4)/7+2x
(21-14x)/7+2x
7(3-2x)/7+2x
3-2x+2x
3
c)
adunam cele doua relatii si obtinem
0,5x+1/4y+1/2x-0,25y=3+1
x=4
0,5*4+y/4=3
2+y/4=3
8+y=12
y=4
asta daca am inteles bine fractia