Question

d) 6 x - 8 = 4 (-2 x + 5)
e) 3(2x-2) = 2(3x + 9)
f) 3 (4x + 7 ) = 4x - 25
g)7x + 5 = 3 ( 3x - 7)

Answer 1

d)6x - 8 = 4(-2x) + 4(5)
   6x - 8 = -8x + 20
   6x + 8x = 20 + 8
   14x = 28
    x = $\frac{28}{14}$
    x = 2

f) 3 (4x + 7 ) = 4x - 25
   3(4x) + 3(7) = 4x - 25
   12x + 21 = 4x -25
    12x - 4x = -25 - 21
     8x = -46
     x= $\frac{-46}{8} = \frac{-23}{4}$

g)7x + 5 = 3 ( 3x - 7)
   7x + 5 = 3(3x) - 3(7)
   7x + 5 = 9x - 21
   5 + 21 = 9x - 7x
   26 = 2x
   $\frac{26}{2}$ = x
   13 = x


Comprobación:

d)6x - 8 = 4(-2x) + 4(5)
   6x - 8 = -8x + 20
   6(2) - 8 = -8(2) + 20
   12 - 8 = -16 + 20
   4 = 4

f) 3 (4x + 7 ) = 4x - 25
   3(4x) + 3(7) = 4x - 25
   12x + 21 = 4x -25
    12($\frac{-23}{4}$) + 21 = 4($\frac{-23}{4}$) - 25
    -69 + 21 = -23 - 25
    -48 = -48

g)7x + 5 = 3 ( 3x - 7)
   7x + 5 = 3(3x) - 3(7)
   7x + 5 = 9x - 21
   7(13) + 5 = 9(13) - 21
   91 + 5 = 117 - 21
   96 = 96

Answer 2

6 x - 8 = 4(-2 x + 5)
6x - 8  =  -8x + 20
8x+6x  = 20 + 8
14x = 28
x = 28/14
x = 2

3(2x-2) = 2(3x + 9)
6x - 6 = 6x + 18
6x-6x = 18  + 6
0x = 24
0 = 24

3(4x + 7 ) = 4x - 25
12x + 21 = 4x - 25
12x - 4x = -25 -21
8x = -46
x = -46/8
x = -6

7x + 5 = 3(3x - 7)
7x + 5 = 9x - 21
5 + 21 = 9x - 7x
26 = 2x
26/2 = x
13 = x