A.  3x + 7 = 28

<=> 3x = 28 - 7
<=> 3x = 21

<=> x = 21/3
<=> x = 7

Proef:

LL = RL = 28

D.  7 + 4x = 39

<=> 4x = 39 - 7
<=> 4x = 32

<=> 32/4
<=> x = 8

Proef:

LL = RL = 39

G.  3x - 7 = 41

<=> 3x = 41 + 7
<=> 3x = 48

<=> 48/3
<=> x = 16

Proef:

LL = RL = 41

B.  4x + 9 = 53

<=> 4x = 53 - 9
<=> 4x = 44

<=> x = 44/11
<=> x = 11

Proef:

LL = RL = 53

E.  12 + 3x = 15

<=> 3x = 15-12
<=> 3x = 3

<=> x = 3/3
<=> x = 1

Proef:

LL = RL = 15

H.  12 - 4x = 4

<=> -4x = 4 - 12
<=> -4x = - 8

<=> x = -8/-4
<=> x = 2

Proef:

LL = RL = 4

C.  2x + 3 = 11

<=> 2x = 11 - 3
<=> 2x = 8

<=> x = 8/2
<=> x = 4

Proef:

LL = RL = 11

F.  2x - 8 = 20

<=> 2x = 20 + 8
<=> 2x = 28

<=> x = 28/2
<=> x = 14

Proef:

LL = RL = 20

I.  5 - 8x = -11

<=> -8x = -11 - 5
<=> -8x = -16

<=> x = -16/-8
<=> x = 2

Proef:

LL = RL = -11