Toán Lớp 6: Tìm x, biết : a, 2.x/3 = -5/6 ; b, 2.x+1/3=x-5/2 ; c, 4.(x-2)^2/3=12
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Toán Lớp 6: Tìm x, biết : a, 2.x/3 = -5/6 ; b, 2.x+1/3=x-5/2 ; c, 4.(x-2)^2/3=12
Comments ( 2 )
a) (2x)/3 = -5/6
=> 2x.6 = -5 . 3
=> 12x = -15
=> x = -15 : 12
=> x = -5/4
b) (2x + 1)/3 = (x – 5)/3
=> 2(2x + 1) = 3(x – 5)
=> 4x + 2 = 3x – 15
=> 3x – 4x = 2 + 15
=> -x = 17
=> x = -17
c) (4(x – 2)^2)/3 = 12
=> 4(x – 2)^2 = 3 . 12
=> 4(x – 2)^2 = 36
=> (x – 2)^2 = 36 : 4
=> (x – 2)^2 = 9
=> (x – 2)^2 = (±3)^2
=> x – 2 in {3; -3}
=> x in {5; -1}
$\textit{Lâm###}$
Lời giải và giải thích chi tiết:
a)2x3=−56
⇔2x=−56.3
⇔2x=−52
⇔x=−52:2
⇒x=−54
b)2.x+1/3=x−5/2
⇔2x+1=(x−5/2).3
⇔ 2x+1=3x−15/2
⇔ 3x−2x=1+15/2
⇒ x=17/2
c)4.(x−2)2/3=12
⇔4.(x−2)2=12.3
⇔4.(x−2)2=36
⇔(x−2)2=36:4
⇔(x−2)2=9
⇔(x−2)2=(±3)2
⇒x−2∈{3;−3}
⇒x∈{5;−1}
$\text{Xin 5* và câu trả lời hay nhất nha}$