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\(\text{a) 5(2x-3)-4(5x-7)=19-2(x+11)}\)
\(10x-15-20x+28=19-2x-22\)
\(10x-20x+2x=19-22-28+15\)
\(-8x=-16\)
\(\Rightarrow x=2\)
\(\text{b) 4(x+3)-7x+17=8(5x-1)+166}\)
\(4x+12-7x+17=40x-8+166\)
\(4x-7x-40x=-8+166-17-12\)
\(-43x=129\)
\(x=-3\)
\(\text{c) 17-14(x+1)=13-4(x+1)-5(x-3)}\)
\(17-14x+14=13-4x-4-5x+15\)
\(-14x+4x+5x=13-4+15-14-17\)
\(-5x=-7\)
\(x=\frac{7}{5}\)
\(\text{d) 5x+3,5+(3x-4)=7x-3(x-0,5)}\)
\(5x+3,5+3x-4=7x-3x+1,5\)
\(5x+3x-7x+3x=1,5-3,5\)
\(x=-2\)
\(\text{e) 7(4x+3)-4(x-1)=15(x+0,75)+7}\)
\(28x+21-4x+4=15x+11,25+7\)
\(28x-4x-15x=11,25+7-4-21\)
\(9x=\frac{-27}{4}\)
\(x=\frac{-3}{4}\)
\(\text{f) 3x+2,42+o,8x=3,38-0,2x}\)
\(3x+0,8x+0,2x=3,38-2,42\)
\(4x=\frac{24}{25}\)
\(x=\frac{6}{25}\)
chúc bạn học tốt !!
b: \(\Leftrightarrow\dfrac{-3x^2+36x+12}{3\left(x+4\right)\left(x-1\right)}=\dfrac{36\left(x-1\right)}{3\left(x+4\right)\left(x-1\right)}+\dfrac{12\left(x+4\right)}{3\left(x-1\right)\left(x+4\right)}\)
\(\Leftrightarrow-3x^2+36x+12=36x-36+12x+48\)
\(\Leftrightarrow-3x^2+36x+12-48x-12=0\)
\(\Leftrightarrow3x\left(x+4\right)=0\)
=>x=0(nhận) hoặc x=-4(loại)
a) 17 - 14( x + 1 ) = 13 - 4( x + 1 ) - 5( x - 3 )
<=> 17 - 14x - 14 = 13 - 4x - 4 - 5x + 15
<=> 17 - 14 - 13 + 4 - 15 = -4x - 5x + 14x
<=> -21 = 5x
<=> x = -21/5
b) 7( 4x + 3 ) - 4( x - 1 ) = 15( x + 0, 75 ) + 7
<=> 28x + 21 - 4x + 4 = 15x + 45/4 + 7
<=> 28x - 4x - 15x = 45/4 + 7 - 21 - 4
<=> 9x = -27/4
<=> x = -3/4
c) 3x( x + 1 ) - 2x( x + 2 ) = x2 - 1
<=> 3x2 + 3x - 2x2 - 4x = x2 - 1
<=> 3x2 + 3x - 2x2 - 4x - x2 = -1
<=> -x = -1
<=> x = 1
a, \(17-14\left(x+1\right)=13-4\left(x+1\right)-5\left(x-3\right)\)
\(\Leftrightarrow17-14x-14=13-4x-4-5x+15\)
\(\Leftrightarrow3-14x=24-9x\Leftrightarrow3-14x-24+9x=0\)
\(\Leftrightarrow-21-5x=0\Leftrightarrow5x=-21\Leftrightarrow x=-\frac{21}{5}\)
b, \(7\left(4x+3\right)-4\left(x-1\right)=15\left(x+0,75\right)+7\)
\(\Leftrightarrow28x+21-4x+1=15x+\frac{45}{4}+7\)
\(\Leftrightarrow9x=-\frac{27}{4}\Leftrightarrow x=-\frac{3}{4}\)
c, \(3x\left(x+1\right)-2x\left(x+2\right)=x^2-1\)
\(\Leftrightarrow3x^2+3x-2x^2-4x=x^2-1\)
\(\Leftrightarrow x^2-x=x^2-1\Leftrightarrow x=1\)
a) 13 - 2x = x- 2 b)2x-15+8x=7-2x+14 c)12-4y+3y=4y-10-8y
<=>13 + 2 = x+2x <=>2x +2x+8x =7+14+15 <=>12+10 =4y-8y+4y-3y
<=> 15 =3x <=>12x =36 <=> 22 =-3y
<=> x=5 <=>x=3 <=>y=-22/3
vậy S=[5] vậy S=[3] vậy S=[-22/3]
b: =>1/4x+4/5-x-5=1/3x+1-1/2x+1
=>-3/4x+1/6x=2+5-4/5=24/5
=>x=-288/35
c: =>6x^2+3x-30x-15=6x^2+10x-21x-35
=>-27x-15=-11x-35
=>-16x=-20
=>x=5/4
a) \(\left(x-2\right)^2=\left(x-4\right)\left(x+4\right)\)
\(\Leftrightarrow x^2-4x+4-x^2+16=0\)
\(\Leftrightarrow20-4x=0\)
\(\Leftrightarrow4x=20\)
\(\Leftrightarrow x=5\)
Vậy S = {5}
b) ĐKXĐ: \(x\ne0;x\ne-2\)
\(\dfrac{x+2}{x}=\dfrac{\left(x+1\right)\left(x+4\right)}{x^2+2x}+\dfrac{x}{x+2}\)
\(\Leftrightarrow\dfrac{x+2}{x}=\dfrac{x^2+4x+x+4+x^2}{x\left(x+2\right)}\)
\(\Leftrightarrow\dfrac{x+2}{x}=\dfrac{2x^2+5x+4}{x\left(x+2\right)}\)
\(\Rightarrow x\left(x+2\right)^2=x\left(2x^2+5x+4\right)\)
\(\Leftrightarrow x^3+4x^2+4x=2x^3+5x^2+4x\)
\(\Leftrightarrow x^3+x^2=0\)
\(\Leftrightarrow x^2\left(x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x^2=0\\x+1=0\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=0\left(loại\right)\\x=-1\left(TM\right)\end{matrix}\right.\)
Vậy S = {-1}
c) Câu này mình không chắc về đề lắm! Bạn dùng ô chữ M bị ngược để viết lại đề nhé!
a) Ta có: \(\left(x-2\right)^2=\left(x-4\right)\left(x+4\right)\)
\(\Leftrightarrow x^2-4x+4=x^2-16\)
\(\Leftrightarrow x^2-4x+4-x^2+16=0\)
\(\Leftrightarrow-4x+20=0\)
\(\Leftrightarrow-4x=-20\)
hay x=5
Vậy: S={5}
Mình làm mẫu câu a nha
a, pt <=> ( x-2/7 - 1 ) + ( x-1/8 - 1 ) = ( x-4/5 - 1 ) + ( x-3/6 - 1 )
<=> x-9/7 + x-9/8 = x-9/5 + x-9/6
<=> x-9/5 + x-9/6 - x-9/7 - x-9/8 = 0
<=> (x-9).(1/5+1/6-1/9-1/8) = 0
<=> x-9 = 0 ( vì 1/5+1/6-1/9-1/8 > 0 )
<=> x = 9
Vậy x = 9
Tk mk nha