Question

Aflati solutiile reale ale ecuatiilor:
a)7x+6pe 30-2x-9pe 12=2x+13pe 30-x+8pe 20+2pe 3
b)3x+7pe 10-4x-9pe 18=12x+7pe 45+1pe 10
c)3x+14pe 4+2x+13pe 5-3pe 4=5x+12pe 5+x+38pe10-11pe20
URGENT!
RASPUNSURI CORECTE:a)x=-5 b)x=5 c)x=6
OFER CORONITA!
MULTUMESC!

Answer 1

a) (7x+6)/30-(2x+13)/30-(2x-9)/12+(x+8)/20=2/3
[2(7x+6)-2(2x+13)-5(2x-9)+3(x+8)]/60=2/3
(14x+12-4x-26-10x+45+3x+24)/60=2/3
(3x+55)/60=2/3
3(3x+55)=2·60
9x+165=120
9x=120-165
9x=-45
x=-45/9
x=-5

b) (3x+7)/10-(4x-9)/18-(12x+7)/45=1/10
[9(3x+7)-5(4x-9)-2(12x+7)]/90=1/10
(27x+63-20x+45-24x-14)/90=1/10
(-17x+94)/90=1/10
10(-17x+94)=90
-170x+940=90
-170x=90-940
-170x=-850    inmultim -1
170x=850
x=850/170
x=5

c) (3x+14)/4+(2x+13)/5-(5x+12)/5-(x+38)/10=3/4-11/20
[5(3x+14)+4(2x+13)-4(5x+12)-2(x+38)]/20=(3·5-11)/20
15x+70+8x+52-20x-48-2x-76=15-11
x-2=4
x=4+2
x=6