Answer: #20, x = 3
               #21,  x = 1/2
Step-by-step explanation:
#20) x + 4 + x + 2+ x + 5  = x + 3 +x+3+x+1+x+1
3x + 11 = 4x + 8
<u>-3x           -3x</u>
       11= x + 8
   <u>   - 8       - 8</u>
      3   =   x
#21)  12x(5) = 6x + 9 + x + 10 + x + 7
          60x =8x + 26
        <u>   -8x    -8x</u>
          52x = 26
  divide both sides by 52
          x = 1/2