Toán Lớp 6: (-12+3x).(2x-34)=0
3.(x-26)+54= 18
(99+11x).(4x^2-16)=0
92-7.(3x+5)=15
(x+3)^3 +1= (-31).2^2
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Toán Lớp 6: (-12+3x).(2x-34)=0
3.(x-26)+54= 18
(99+11x).(4x^2-16)=0
92-7.(3x+5)=15
(x+3)^3 +1= (-31).2^2
Giup mềnh zới ạ:”(
Comments ( 2 )
(-12 + 3x) . (2x-34) =0
=> -12+3x=0 hoặc 2x-34=0
+) -12 + 3x = 0
=> 3x =12
=> x = 4
+) 2x – 34 =0
=> 2x = 34
=> x = 17
Vậy x \in {4;17}
b)
3 (x-26) + 54 = 18
=> 3 (x-26) = 18 -54
=> 3 (x-26) = -36
=> x-26=-36:3
=>x-26=-12
=>x=-12 + 26
=>x=14
Vậy x=14
c)
(99 + 11x)(4x^2-16)=0
=> 99+11x=0 hoặc 4x^2 -16=0
+)99 + 11x =0
=> 11x= -99
=> x=-9
+)4x^2-16=0
=>4x^2=16
=>x^2=4
=>x^2 = (+-2)^2
=>x=+-2
Vậy x \in {-9 ; 2 ; -2}
d)
92 – 7 (3x+5) =15
=> 7 (3x+5) = 92 – 15
=> 7 (3x+5) = 77
=> 3x+5=77:7
=>3x+5=11
=>3x=11-5
=>3x=6
=>x=6:3
=>x=2
Vậy x=2
e)
(x+3)^3 + 1 = (-31) . 2^2
=> (x+3)^3 = (-31) . 2^2 – 1
=> (x+3)^3 = -31. 4-1
=>(x+3)^3 = -124-1
=>(x+3)^3 =-125
=> (x+3)^3 = (-5)^3
=>x+3=-5
=>x=-8
Vậy x=-8
1) (-12+3x).(2x-34)=0
<=> -12 + 3x = 0 V 2x – 34 = 0
<=> x = 4 V x = 17
2) 3.(x-26)+54= 18
<=> 3x – 78 + 54 = 18
<=> 3x -24 = 18
<=> 3x = 42
<=> x = 14
3) (99+11x).(4x^2-16)=0
<=> 99 + 11x = 0 V 4x^2 – 16 = 0
<=> 11x = -99 V 4x^2 = 16
<=> x = -9 V x^2 = 4
<=> x = -9 V x = 2 V x = -2
4) 92-7.(3x+5)=15
<=> 7(3x+5) = 77
<=> 3x + 5 = 11
<=> 3x = 6
<=> x =2
5) (x+3)^3 +1= (-31).2^2
<=> (x+3)^3 = -124 – 1
<=> (x+3)^3 = -125
<=> (x+3)^3 = (-5)^3
<=> x + 3 = -5
<=> x = -8