Question

Va rog frumos! Dau coroana! Doar cele incercuite. Va rog!

Answer 1

11.
b)(2-2x)/5 · 5/2 = 16/100 
   2(1-x)/5 · 5/2 = 4/25
   1-x=4/25 =>25-25x=4 =>-25x=-21 =>x=21/25

d)3/7 · 3(1+x)/7 = -1
   9(1+x)/49 = -1
   9+9x=-49 =>9x=-58 =>x=-58/9

f)(4-5)/20 · 7/3 - x/4 = 4/5
  -7/60 - x/4 = 4/5
  -7-15x=48 =>-15x=55 =>x=-55/15=-11/3

13.
a)3(x+4)-5(x+2)=2x-5(x+1)
   3x+12-5x-10=2x-5x-5
   -2x+2=-3x-5 =>x=-7

c)10x-2(x+7)=5(x-1)-4(x+1)+11
   10x-2x-14=5x-5-4x-4+11
   8x-14=x+2 
   7x=16 =>x=16/7

e)6(3x-2)-15(x-7)=75-6(2x-9)
   18x-12-15x+105=75-12x+54
    3x+93=129-12x
    15x=36 =>x=36/15=12/5

g)6(4x-3)-7(3-x)=3(2x+1)+13
   24x-18-21+7x=6x+3+13
   31x-39=6x+16
   25x=55 =>x=55/25=11/5

14.
a)3x+15-6x+12=4x+8-5x+20
   -3x+27=-x+28
   -2x=1 =>x=-1/2

b)4x+14+3x-3=6x+18-18
   7x+11=6x =>x=-11

c)15x-15+8-12x=9-2x-8
   3x-7=-2x+1
   5x=8 =>x=8/5