Toán Lớp 6: 5x+19 chia hết cho 2x+1 GẤPPPPPP

Question

Toán Lớp 6:  5x+19 chia hết cho 2x+1 GẤPPPPPP

haiyemy · Answer

5x+19 $ vdots$ 2x+1     &rArr;$ left  { {{5x+19  vdots 2x+1}  atop {10x+38  vdots 10x+5}}  right.$      &rArr;$ left  { {{10x+38  vdots 10x+5}  atop {10x+5  vdots10x+5}}  right.$      &rArr;(10x+38)-(10x+5) $ vdots$ 10x+5     &rArr;10x+38-10x-5 $ vdots$ 10x+5     &rArr;33  $ vdots$ 10x+5     &rArr;10x+5&isin;Ư(33)     &rArr;10x+5&isin;{&plusmn;1;&plusmn;3;&plusmn;11;&plusmn;33}     &rArr;x&isin;{0;-1;-2;1;-6;5;-17;16}     Vậy x&isin;{0;-1;-2;1;-6;5;-17;16}

doanthulan · Answer

5x+19 vdots 2x+1 =>2(5x+19) vdots 2x+1 =>10x+38 vdots 2x+1 =>10x+5+33 vdots 2x+1 =>5(2x+1)+33 vdots 2x+1 V&igrave; 5(2x+1) vdots 2x+1 5(2x+1)+33 vdots 2x+1 =>33 vdots 2x+1 =>2x+1&isin;Ư(33)={+-1;+-3;+-11;+-33} =>2x&isin;{0;-2;-4;2;-12;10;-34;32} =>x&isin;{0;-1;-2;1;-6;5;-17;16} Vậy 5x+19 vdots 2x+1=>x&isin;{0;-1;-2;1;-6;5;-17;16} - T&iacute;nh chất : a+-b vdots m $ begin{cases}a vdots m&rArr;b vdots m   b vdots m&rArr;a vdots m end{cases}$