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3.2x - 3.6 - 4+4.2x - 2x-2.(-4) = 4 - 3+3.2x - 5-5.(-2x)
6x -18 -4 +8x -2x +8 = 4 -3 +6x -5 +10x
6x +8x -2x -18-4+8 = 4-3-5+6x+10x
12x-22 = -4+16x
12x-16x = -4+22
-4x = 18
x = 18: (-4)
x = -4,5
Mình không chắc là đúng đâu đấy, tại giải vội quá, nếu sai thì ming bạn thông cảm ^.^
a) \(\left(x-1\right)^3=8=2^3\)
\(x-1=2\)
\(x=2+1=3\)
b) \(7^{2x-6}=49=7^2\)
\(2x-6=2\)
\(2x=6+2=8\)
\(x=8:2=4\)
c) \(\left(2x-14\right)^7=128=2^7\)
\(2x-14=2\)
\(2x=14+2=16\)
\(x=16:2=8\)
d) \(x^4\cdot x^5=5^3\cdot5^6=5^4\cdot5^5\)
\(x=5\)
e) \(3\cdot\left(x+2\right):7\cdot4=120\)
\(x+2=120:3\cdot7:4\)
\(x+2=70\)
\(x=70-2=68\)
Lời giải:
a. $(x-1)^3=8=2^3$
$\Rightarrow x-1=2$
$\Rightarrow x=3$
b. $7^{2x-6}=49=7^2$
$\Rightarrow 2x-6=2$
$\Rightarrow 2x=8$
$\Rightarrow x=4$
c. $(2x-14)^7=128=2^7$
$\Rightarrow 2x-14=2$
$\Rightarrow 2x=16$
$\Rightarrow x=18$
d.
$x^4.x^5=5^3.5^6$
$x^9=5^9$
$\Rightarrow x=5$
e.
$3(x+2):7=120:4=30$
$3(x+2)=30.7=210$
$x+2=210:3=70$
$x=70-2=68$
a,3x-10=2x+13
\(\Rightarrow\)3x-2x=10+13
\(\Rightarrow\)x=23
b,x+12=-5-x
\(\Rightarrow\)x+x=-12-5
\(\Rightarrow\)2x=-17
\(\Rightarrow\)x=-8,5
c,x+5=10-x
\(\Rightarrow\)x+x=-5+10
\(\Rightarrow\)2x=5
\(\Rightarrow\)x=2,5
e,12-x=x+1
\(\Rightarrow\)-x-x=-12+1
\(\Rightarrow\)-2x=-11
\(\Rightarrow\)x=5,5
f,14+4x=3x+20
\(\Rightarrow\)4x-3x=-14+20
\(\Rightarrow\)x=6
g,2.(x-1)+3(x-2)=x-4
\(\Rightarrow\)2x-2+3x-6=x-4
\(\Rightarrow\)2x-2+3x-6-x+4=0
\(\Rightarrow\)4x-4=0
\(\Rightarrow\)4x=4
\(\Rightarrow\)x=1
h,3(4-x)-2(x-1)=x+20
\(\Rightarrow\)12-3x-2x+2-x-20=0
\(\Rightarrow\)-6x-6=0
\(\Rightarrow\)-6x=6
\(\Rightarrow\)x=-1
i,4(2x+7)-3(3x-2)=24
\(\Rightarrow\)8x+28-9x+6=24
\(\Rightarrow\)-x+34=24
\(\Rightarrow\)-x=-10
\(\Rightarrow\)x=10
k,3(x-2)+2x=10
\(\Rightarrow\)3x-6+2x=10
\(\Rightarrow\)5x-6=10
\(\Rightarrow\)5x=16
\(\Rightarrow\)x=3,2
Phần d, tớ không biết làm!!!!
Câu 1:
\(\Leftrightarrow6x-18-8x-4-2x+8=4-3\left(2x+1\right)+5\left(2x-1\right)\)
=>-4x-14=4-6x-3+10x-5
=>-4x-14=4x-4
=>-8x=10
hay x=-5/4
\(3\left(2x-6\right)-4\left(1+2x\right)-2\left(x-4\right)=4-3\left(1+2x\right)-5\left(1-2x\right).\)
\(\Leftrightarrow6x-18-4-8x-2x+8=4-3-6x-5+10x\)
\(\Leftrightarrow-4x-14=4x-4\)
\(\Leftrightarrow-4x-4x=-4+14\)
\(\Leftrightarrow-8x=10\)
\(\Leftrightarrow x=-\frac{5}{4}\)