Toán Tìm x biết : 28/11/2021 By Nevaeh Tìm x biết : a, |5-x| – 1 =6 b, (5-x) – 1 = 6 c, (x-1) mũ 33 = ( x-1 ) mũ 22
Đáp án: a, |5-x| – 1 =6 |5-x| = 6+1 |5-x| = 7 ⇒ 5-x=+7 C1: 5-x=7=>x=-2 C2: 5-x=-7=>x=12 Vậy x ∈{-2 ; 12} b,(5-x) – 1 = 6 5-x-1=6 4-x=6 x=4-6=-2 c, (x-1) = `( x-1 )^22` =`(x-1)^30-`(x-10^22`=0 =`(x-1)^22`.`(x-1)^11`-`(x-1)^22`=0 =`(x-1)^22`.`[(x-1)^11-1]`=0 =`(x-1)^11`-1=0 =`(x-1)^11`=1 =x-1=1 =x=2 Trả lời
a, |5-x| – 1 =6 |5-x| = 6+1 |5-x| = 7 ⇒ 5-x=±7 TH1: 5-x=7⇔x=-2 TH2: 5-x=-7⇔x=12 Vậy x ∈{-2;12} b,(5-x) – 1 = 6 5-x-1=6 4-x=6 x=4-6=-2 c, (x-1)^33 = ( x-1 )^22 ⇔(x-1)^33-(x-1)^22=0 ⇔(x-1)^22.(x-1)^11-(x-1)^22=0 ⇔(x-1)^22.[(x-1)^11-1]=0 ⇔(x-1)^11-1=0 ⇔(x-1)^11=1 ⇔x-1=1 ⇔x=2 Trả lời
Đáp án:
a, |5-x| – 1 =6
|5-x| = 6+1
|5-x| = 7
⇒ 5-x=+7
C1: 5-x=7=>x=-2
C2: 5-x=-7=>x=12
Vậy x ∈{-2 ; 12}
b,(5-x) – 1 = 6
5-x-1=6
4-x=6
x=4-6=-2
c, (x-1) = `( x-1 )^22`
=`(x-1)^30-`(x-10^22`=0
=`(x-1)^22`.`(x-1)^11`-`(x-1)^22`=0
=`(x-1)^22`.`[(x-1)^11-1]`=0
=`(x-1)^11`-1=0
=`(x-1)^11`=1
=x-1=1
=x=2
a, |5-x| – 1 =6
|5-x| = 6+1
|5-x| = 7
⇒ 5-x=±7
TH1: 5-x=7⇔x=-2
TH2: 5-x=-7⇔x=12
Vậy x ∈{-2;12}
b,(5-x) – 1 = 6
5-x-1=6
4-x=6
x=4-6=-2
c, (x-1)^33 = ( x-1 )^22
⇔(x-1)^33-(x-1)^22=0
⇔(x-1)^22.(x-1)^11-(x-1)^22=0
⇔(x-1)^22.[(x-1)^11-1]=0
⇔(x-1)^11-1=0
⇔(x-1)^11=1
⇔x-1=1
⇔x=2