Tìm số nguyên x, biết rằng : a ) ( 3 + x ) . 5 – 14 = – 49 b ) – 72 : ( x – 2 )^3 = 9 c ) x + ( – 12 ) = 16 – x d ) 2| x | + | – x | = 9

a,(3+x)×5-14=-49

⇒15+5x-14=-49

⇔5x+1=-49

⇔ 5x=-50

x=-10

b,-72:(x-2)³=9

⇔(x-2)³=-8

⇒x-2=-2

⇔x=0

c,x+(-12)=16-x

⇔x-12=16-x

⇔2x=4

⇔x=2

d,2|x|+|-x|=9

Nếu x≥0

⇒2|x|+|-x|=9

⇒2x+x=9

⇒3x=9

⇒x=1(t/m)