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\(a,2.\left(x-5\right)-3.\left(x+7\right)=14\)
\(2x-10-3x-21=14\)
\(-x-31=14\)
\(x=-31-14\)
\(x=-45\)
\(b,5.\left(x-6\right)-2\left(x+3\right)=12\)
\(5x-30-2x-6=12\)
\(3x-36=12\)
\(3x=12+36\)
\(3x=48\)
\(x=16\)
\(c,-5.\left(2-x\right)+4.\left(x-3\right)=10.x-15\)
\(-10+5x+4x-12=10x-15\)
\(-6x-22=10x-15\)
\(-6x-10x=-15+22\)
\(-16x=7\)
\(x=-\frac{7}{16}\)
Câu d , e f tương tự nha
-2x - 40 = (5 - x) - (-15 + 60)
-2x - 40 = (5 - x) - 45
-2x - 40 = -40 - x
-2x - x = 40 - 40
-3x = 0
x = 0
2(x - 4) - 3(x + 7) = 14
2x - 8 - 3x - 21 = 14
-x - 29 = 14
-x = 14 + 29
-x = 43
x = -43
-7(5 - x) - 2(x - 10) = 15
-35 + 7x - 2x + 20 = 15
-15 + 5x = 15
5x = 15 + 15
5x = 30
x = 6
a.\(\left(-12\right)x-14=-2\)
\(\left(-12\right)x=-2+14\)
\(\left(-12\right)x=12\)
\(x=12:\left(-12\right)\)
\(x=-1\)
\(b,\left(-8\right)x=\left(-5\right)\left(-7\right)-3\)
\(\left(-8\right)x=35-3\)
\(\left(-8\right)x=32\)
\(x=32:\left(-8\right)\)
\(x=-4\)
\(c,\left(-9\right)x+3=\left(-2\right)\left(-7\right)+16\)
\(\left(-9\right)x+3=14+16\)
\(\left(-9\right)x+3=30\)
\(\left(-9\right)x=30-3\)
\(\left(-9\right)x=27\)
\(x=27:\left(-9\right)\)
\(x=-3\)
x(x+2)=0
suy ra x=0 hoặc x+2=0
5-2x=-7
2x=-7+5
2x=-(7-5)
2x=-2
x=-2:2
x=-1
Vậy x=-1
NHỚ TÍCH MK NHA
Tự học giúp bạn có được một gia tài
Jim Rohn – Triết lý cuộc đời
1a) \(\frac{x-3}{x+7}=\frac{-5}{-6}\)
=> \(\frac{x-3}{x+7}=\frac{5}{6}\)
=> (x - 3).6 = 5.(x + 7)
=> 6x - 18 = 5x + 35
=> 6x - 5x = 35 + 18
=> x = 53
b) \(\frac{x-7}{x+3}=\frac{4}{3}\)
=> (x - 7). 3 = (x + 3). 4
=> 3x - 21 = 4x + 12
=> 3x - 4x = 12 + 21
=> -x = 33
=> x = -33
c) \(\frac{x-10}{6}=-\frac{5}{18}\)
=> (x - 10) . 18 = -5 . 6
=> 18x - 180 = -30
=> 18x = -30 + 180
=> 18x = 150
=> x = 150 : 18 = 25/3
d) \(\frac{x-2}{4}=\frac{25}{x-2}\)
=> (x - 2)(x - 2) = 25 . 4
=> (x - 2)2 = 100
=> (x - 2)2 = 102
=> \(\orbr{\begin{cases}x-2=10\\x-2=-10\end{cases}}\)
=> \(\orbr{\begin{cases}x=12\\x=-8\end{cases}}\)
e) \(\frac{7}{x}=\frac{x}{28}\)
=> 7 . 28 = x . x
=> 196 = x2
=> x2 = 142
=> \(\orbr{\begin{cases}x=14\\x=-14\end{cases}}\)
f) \(\frac{40+x}{77-x}=\frac{6}{7}\)
=> (40 + x) . 7 = (77 - x).6
=> 280 + 7x = 462 - 6x
=> 280 - 462 = -6x + 7x
=> -182 = x
=> x = -182
\(8+\left(x-6\right)=-40\)
\(\Leftrightarrow x-6=-40-8\)
\(\Leftrightarrow x-6=-48\)
\(\Leftrightarrow x=-48+6\)
\(\Leftrightarrow x=-42\)
\(\left(2x+5\right)-\left(-9\right)=-6\)
\(\Leftrightarrow2x+5=-6-9\)
\(\Leftrightarrow2x+5=-15\)
\(\Leftrightarrow2x=-15-5\)
\(\Leftrightarrow2x=-20\)
\(\Leftrightarrow x=\frac{-20}{2}\)
\(\Leftrightarrow x=-10\)
\(2\left(x-5\right)-3\left(x+7\right)=14\)
\(\Leftrightarrow2x-10-3x-21=14\)
\(\Leftrightarrow-x-31=14\)
\(\Leftrightarrow-x=14+31\)
\(\Leftrightarrow-x=45\)
\(\Leftrightarrow x=-45\)
\(-7\left(5-x\right)-2\left(x+3\right)=12\)
\(\Leftrightarrow-35+7x-2x-6=12\)
\(\Leftrightarrow-30x=12+6\)
\(\Leftrightarrow-30x=18\)
\(\Leftrightarrow x=\frac{-3}{5}\)
