(1/3 . X ) : 2/3 = 35 / 8
5 - | - 3X | = 1,7
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\(x-43=35-x-48\)
\(x+x=43+35-48=30\)
2.x=30=> x=15
2) -x+6-85=x+51-54
-x-79=x-3
2x=76=> x=38
3)\(\orbr{\begin{cases}-7-x-3=-3\Rightarrow x=-7\\-7-x-3=3\Rightarrow x=-13\end{cases}}\)
a) Ta có: x-43=(35-x)-48
⇔x-43=35-x-48
⇔x-43=-x-13
⇔x-43+x+13=0
⇔2x-30=0
⇔2(x-15)=0
mà 2≠0
nên x-15=0
hay x=15
b) Ta có: 305-x+14=48+(x-23)
⇔319-x=48+x-23
⇔319-x=x+25
⇔319-x-x-25=0
⇔-2x+294=0
⇔-2x=-294
hay x=147
Vậy: x=147
c) Ta có: -(x-6+85)=(x+51)-54
⇔-x+6-85=x+51-54
⇔-x-79=x-3
⇔-x-79-x+3=0
⇔-2x-76=0
⇔-2x=76
hay x=-38
Vậy: x=-38
d) Ta có: -(35-x)-(37-x)=33-x
⇔-35+x-37+x-33+x=0
⇔3x-105=0
⇔3(x-35)=0
mà 3≠0
nên x-35=0
hay x=35
Vậy: x=35
e) Ta có: 13-|x|=|-4|
⇔13-|x|=4
⇔|x|=9
⇔x∈{9;-9}
Vậy: x∈{9;-9}
f) Ta có: |x|-3+6=16
⇔|x|+3=16
⇔|x|=13
hay x∈{-13;13}
Vậy: x∈{-13;13}
g) Ta có: 35-|2x-1|=14
⇔|2x-1|=21
⇔\(\left[{}\begin{matrix}2x-1=21\\2x-1=-21\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=22\\2x=-20\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=11\\x=-10\end{matrix}\right.\)
Vậy: x∈{11;-10}
h) Ta có: |3x-2|+5=9-x
⇔|3x-2|+5-9+x=0
⇔|3x-2|-4+x=0
⇔|3x-2|=0-(-4+x)
⇔|3x-2|=4-x
⇔\(\left[{}\begin{matrix}3x-2=4-x\\3x-2=x-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}3x-2-4+x=0\\3x-2-x+4=0\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}4x-6=0\\2x+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}4x=6\\2x=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{3}{2}\left(ktm\right)\\x=-1\left(tm\right)\end{matrix}\right.\)
Vậy: x=-1
Bài 1:tính
a)65.(-19)+19.(-35)
=65.(-19)+(-19).35
=(-19).(65+35)
=(-19).100
=-1900
b)85.(35-27)-35.(85-27)
=85.35-85.27-35.85+35.27
=(85.35-35.85)+(-85.27+35.27)
=27.(-85+35)
=27.(-50)
=1350
c)47.(45-15)-47.(45+15)
=47.[(45-15)-(45+15)]
=47.[30-60]
=47.(-30)
=-1410
Bài2: Tìm các số nguyên x biết
a)(-2).(x+6)+6.(x-10)=8
-2x-12+6x-60=8
4x-72=8
4x=72+8
4x=50
x=\(\frac{25}{2}\)
b)(-4).(2x+9)-(-8x+3)-(x+13)=0
-6x-36+8x-3-x-13=0
x-41=0
x=41
Bài 1: Tính
a) \(65.\left(-19\right)+19.\left(-35\right)\)
= \(-1235+-665\)
= \(-1900\)
b) \(85.\left(35-27\right)-35.\left(85-27\right)\)
= \(-1350\)
c) \(47.\left(45-15\right)-47.\left(45+15\right)\)
=\(-1410\)
Bài 2: Tìm x:
\(\left(-2\right).\left(x+6\right)+6.\left(x-10\right)=8\)
\(x=20\)
1: \(=6x^2+2x-15x-5-x^2+6x-9+4x^2+20x+25-27x^3-27x^2-9x-1\)
=-27x^3-18x^2+4x+10
2: =4x^2-1-6x^2-9x+4x+6-x^3+3x^2-3x+1+8x^3+36x^2+54x+27
=7x^3+37x^2+46x+33
5:
\(=25x^2-1-x^3-27-4x^2-16x-16-9x^2+24x-16+\left(2x-5\right)^3\)
\(=8x^3-60x^2+150-125+12x^2-x^3+8x-60\)
=7x^3-48x^2+8x-35