( x + 1) + (x +4) + ...+ ( x + 34) = 222
x*12 + [(1+34) * 12 : 2] = 222
x*12 + 210 = 222
x*12 = 12
x = 1
(x+1)+(x+ 4)+...+(x+34)=222
x*12+(1+4+7...+34)=222
x*12+210=222
x*12=222-210
x*12=12
x=12:12
x=1
các bạn nhớ k cho mình nhé
(x+1)+(x+ 4)+...+(x+34)=222
x\(\cdot\)12+(1+4+7...+34)=222
x\(\cdot\)12+210=222
x\(\cdot\)12=222-210
x\(\cdot\)12=12
x=12:12
x=1
Chú ý : dấu \(\cdot\)là dấu nhân nhé
( x + 1) + ( x + 4 ) + ... + ( x + 34 ) = 222
x × 12 + ( 1 + 4 + 7 + ...+ 34 ) =222
x × 12 + 210 = 222
x × 12 = 222 - 210
x × 12 = 12
x = 12 : 12
x = 1
Vậy x = 1