bad  health but you don know
but am a bad liar
bad liar

4. (x + 1) + (x + 4) + ( x + 7) + . ... + (x  + 28) = 156
<=> x + x + ... + x + (1 + 4 + 7 + ... + 28) = 156
<=> 10*x + [(28 - 1) : 3 + 1]*(28 + 1) : 2 = 156
<=> 10*x  + 145 = 156
<=> 10 * x = 156 - 145
<=> 10 * x = 11
<= > x  = 1,1

B3: 16: [(3/5.x+8)/21 +9]=7/10
(3/5.x+8)/21 +9=16: 7/10
(3/5.x+8)/21 +9=160/7
(3/5x +8)/21= 160/7 -9
3/5x+8 :21=97/7
3/5x+8=97/7.21
3/5x+8=291
3/5x=291-8
3/5x=283
x=283:3/5
x=1415/3