Toán Lớp 6: a) x +16 chia hết cho x
b) x+9 chia hết cho x+1
Giúp mik với!!! ????????????????
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Toán Lớp 6: a) x +16 chia hết cho x
b) x+9 chia hết cho x+1
Giúp mik với!!! ????????????????
Comments ( 2 )
a ) x + 16 \vdots x
=> 16 \vdots x Vì x \vdots x
=> x ∈ Ư(16) = {±1 ; ±2 ;±4 ; ±8 ; ± 16}
Vậy x∈ {±1 ; ±2 ;±4 ; ±8 ; ± 16}
b ) x + 9 \vdots x + 1
=> ( x + 1 ) + 8 \vdots x + 1
=> 8 \vdots x + 1 Vì (x + 1 ) \vdots x + 1
=> x + 1 ∈ Ư(8) = {-8 ; -4 ; -2 ; -1 ; 1 ; 2 ; 4 ; 8}
=> x ∈ {-9 ; -5 ; -3 ; -2 ; 0 ; 1 ; 3 ; 7}
Vậy x ∈ {-9 ; -5 ; -3 ; -2 ; 0 ; 1 ; 3 ; 7}
#dtkc
a) x+16 $\vdots$ x
Vì x $\vdots$ x nên 16 $\vdots$ x
⇒x∈Ư(16)={±1;±2;±4,±8±16}
Vậy x∈{±1;±2;±4,±8±16}
b) x+9=x+1+8
=(x+1)+8
Vì x+1$\vdots$x+1 nên 8$\vdots$x+1
⇒x+1∈Ư(8)={±1;±2;±4±;8}
⇒x∈{-9;-5;-3;-2;0;1;3;7}