1.
a)
5(2-x)-4x=3-(2x-1)
10-5x-4x=3-2x+1
10-3-1=-2x+5x+4x
6=7x
=>x=6/7
b)
2x-(x+2)(x-2)=5-x²+1
2x-x²-4=5-x²+1
2x=6+4
2x=10
x=10/2
x=5
2.
|5x-4|=6
5x-4=6 sau 5x-4=-6
5x=10 5x=-2
x=2 x=-2/5
4.
4-(x-2)²>x(1-x)
4-(x²-2x+4)>x-x²
4-x²+2x-4>x-x²
2x>x
2x-x>0
x>0
Deci x este mai mic decat 0 , deci apartine ( - infinit; 0)
6.
Notez:
a-2 camere
b-3 camere
a+b=102
2a+3b=238
2a+2b+b=238
2(a+b)+b=238
204+b=238
b=34
a=102-34
a=68
Exercitiile 3 si 5 le ai in imaginea de mai jos:
