Question

-resolva as equações,sendo x um número racional.
a)39x+78=0
b)350x-500= 100x+750 
c)5(3-x)= 4x+18
d)-2(2x+1)-3(x-5)= -8       

Answer 1

a)39x+78=0
x= 78/39
x= 2

b)350x-500= 100x+750 
350x -100x = 750 +500
250x = 1250
x= 1250/250
x= 5

c)5(3-x)= 4x+18
15 -5x = 4x +18
-5x -4x = 18 -15
-9x = 3.(-1)
9x = -3
x= -3/9   simplificando -3 e 9 por 3
x= -1/3

d)-2(2x+1)-3(x-5)= -8  
-4x -2 -3x +15 = -8
-4x -3x = -8 -15 +2
-7x = -23 +2
-7x = -21.(-1)
7x = +21
x= 21/7
x= 3

Answer 2

a)39x+78=0
   39x= 78
   x=78/39
   x=2

b)350x-500= 100x+750
  350x-100x=750+500
  250x=1250
  x=5

c)5(3-x)= 4x+18
  15-5x=4x+18
  -5x-4x= 18-15
 -9x= 3
   x= 3/ -9
   Simplificando por 3
 x= -1/3

d)-2(2x+1)-3(x-5)= -8  
   -4x-2-3x+15= -8
  -4x-3x=-8-15+2
  -7x= -21
  x= -21/-7
  x= 3