Question

ex 13 
rezolvati in R  ECUATIA
a)5(3x-6)+4(3-2x)=5x-8
b)9(x-3)-4(7-3x)=5-3x
c)$2 \frac{3}{8} ( \frac{1}{3} -3x)+ \frac{5}{8} ( \frac{1}{3} -3x)=1$
d)$\frac{15-x}6{} - \frac{2x+16}{5} =1$

Answer 1

a) 5(3x - 6) + 4(3 - 2x) = 5x - 8
    15x - 30 + 12 - 8x = 5x - 8
    15x - 8x - 5x = 30 - 12 - 8
    2x = 10
    x = 5
b) 9(x - 3 ) - 4(7 - 3x) = 5 - 3x
   9x - 27 - 28 + 12x = 5 - 3x
   9x + 12x + 3x = 27 + 28 + 5
   24x = 60
     x = 2,5
c) 2 3/8 ( 1/3 - 3x ) + 5/8 ( 1/3 - 3x ) = 1
   19/8 ( 1/3 - 3x ) + 5/8 ( 1/3 - 3x ) = 1
   19/24 - 57/8x + 5/24 - 15/8x = 1
   -72/8x + 24/24 = 1
   -9x + 1 = 1
   -9x = 0
   x = 0
d) 15-x / 6 - 2x+16 / 5 = 1
   5(15 - x ) - 6(2x + 16 ) = 30
   75 - 5x - 12x - 96 = 30
   -17x = 30 - 75 + 96
   -17x = 51
     x = -3

Answer 2

a)5(3x-6)+4(3-2x)=5x-8
15x-30+12-8x=5x-8
7x--18=5x-8
7x-5x=18-8
2x=10
x=10/2
x=5

b)9(x-3)-4(7-3x)=5-3x
9x-27-28+12x=5-3x
21x-55=5-3x
21x+3x=55+5
24x=60
x=60/24
x=2,5

c)
19/8(1/3-3x)+5/24-15x/8=1
19/24-57x/8+5/24-15x/8=1
-72x/8+24/24=1
-9x+1=1
-9x=1-1
-9x=0
x=0

d)
[5(15-x)-6(2x+16)]/30=1
75x-5x-12x-96=30
63x-101=30
63x=101+30
63x=131
x=131/63