b,(x+1/2).(2/3-2x) c,(x+1/50)²+17/25=26/25 d,25/4.x-11/2.x=25% f,(1/2+3/4-1/2):(-5/6) 19/08/2021 Bởi Peyton b,(x+1/2).(2/3-2x) c,(x+1/50)²+17/25=26/25 d,25/4.x-11/2.x=25% f,(1/2+3/4-1/2):(-5/6) { "@context": "https://schema.org", "@type": "QAPage", "mainEntity": { "@type": "Question", "name": " b,(x+1/2).(2/3-2x) c,(x+1/50)²+17/25=26/25 d,25/4.x-11/2.x=25% f,(1/2+3/4-1/2):(-5/6)
Đáp án: b) thieu de c) (x+1/50)^2 + 17/25 = 26/25 (x+1/50)^2 = 9/25 (x+1/50)^2 = (3/5)^2 = (-3/5)^2 => x+1/50 ∈ { 3/5, -3/5 } TH1: x + 1/50 = 3/5 x = 29/50 TH2: x + 1/50 = -3/5 x = -31/50 vay x ∈ {29/50, -31/50} d ) 25/4 x -11/2 x = 25% <-> 3/4 x = 0,25 <-> x = 1/3 f ) (1/2 +3/4-1/2) : -5/6 <x < 4/21 : 4/-7 <-> 3/4 : -5/6 <x < -1/3 <-> -9/10<x< -1/3 Bình luận
Đáp án: Giải thích các bước giải: b) ( x+ 1/2) .( 2/3-2x) = 2/3x + 1/3 -2x^2 – x = -2x^2 -1/3 x +1/3 c ) ( x+ 1/50 )^2 +17/25= 26/25 <-> (x+ 1/50 ) ^2 = 9/25 <-> (x+1/50)^2 = ( 3/5)^2 <-> x+1/50=3/5 or x+1/50=-3/5 <-> x= 29/50 or x= -31/50 d ) 25/4 x -11/2 x = 25% <-> 3/4 x = 0,25 <-> x = 1/3 f ) (1/2 +3/4-1/2) : -5/6 <x < 4/21 : 4/-7 <-> 3/4 : -5/6 <x < -1/3 <-> -9/10<x< -1/3 Bình luận
Đáp án:
b) thieu de
c) (x+1/50)^2 + 17/25 = 26/25
(x+1/50)^2 = 9/25
(x+1/50)^2 = (3/5)^2 = (-3/5)^2
=> x+1/50 ∈ { 3/5, -3/5 }
TH1: x + 1/50 = 3/5
x = 29/50
TH2: x + 1/50 = -3/5
x = -31/50
vay x ∈ {29/50, -31/50}
d ) 25/4 x -11/2 x = 25%
<-> 3/4 x = 0,25
<-> x = 1/3
f ) (1/2 +3/4-1/2) : -5/6 <x < 4/21 : 4/-7
<-> 3/4 : -5/6 <x < -1/3
<-> -9/10<x< -1/3
Đáp án:
Giải thích các bước giải:
b) ( x+ 1/2) .( 2/3-2x)
= 2/3x + 1/3 -2x^2 – x
= -2x^2 -1/3 x +1/3
c ) ( x+ 1/50 )^2 +17/25= 26/25
<-> (x+ 1/50 ) ^2 = 9/25
<-> (x+1/50)^2 = ( 3/5)^2
<-> x+1/50=3/5 or x+1/50=-3/5
<-> x= 29/50 or x= -31/50
d ) 25/4 x -11/2 x = 25%
<-> 3/4 x = 0,25
<-> x = 1/3
f ) (1/2 +3/4-1/2) : -5/6 <x < 4/21 : 4/-7
<-> 3/4 : -5/6 <x < -1/3
<-> -9/10<x< -1/3