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\((x-2)^3-(x+5)(x^2-5x+25)+6x^2=11\\\Leftrightarrow (x-2)^3-(x+5)(x^2-5.x+5^2)+6x^2=11 \\\Leftrightarrow x^3-6x^2+12x-8 -(x^3+5^3)+6x^2-11=0 \\\Leftrightarrow 12x-144=0 \\\Leftrightarrow x=12\)
Vậy \(x=12\).
(x−2)3−(x+5)(x2−5x+25)+6x2=11
=>(x−2)3−(x+5)(x2−5.x+52)+6x2=11
=>x3−6x2+12x−8−(x3+53)+6x2−11=0
=>12x−144=0
=>x=12(x−2)3−(x+5)(x2−5x+25)+6x2=11
=>(x−2)3−(x+5)(x2−5.x+52)+6x2=11
=>x3−6x2+12x−8−(x3+53)+6x2−11=0
=>12x−144=0
=>x=12
Vậy x=12x=12.
cho tôi đúng đi
a, \(\left(x-3\right)\left(x^2+3x+9\right)-x\left(x+4\right)\left(x-4\right)=5\)
\(\Rightarrow x^3+3x^2+9x-3x^2-9x-27-x\left(x^2-16\right)=5\)
\(\Rightarrow x^3-27-x^3-16x=5\)
\(\Rightarrow-16x-27=5\)
\(\Rightarrow-16x=32\Rightarrow x=-2\)
b, \(\left(x-2\right)^3-\left(x+5\right)\left(x^2-5x+25\right)+6x^2=11\)
\(\Rightarrow x^3-6x^2+12x-8-\left(x^3-5x^2+25x+5x^2-25x+125\right)+6x^2=11\)
\(\Rightarrow x^3-6x^2+12x-8-x^3-125+6x^2=11\)
\(\Rightarrow12x-133=11\Rightarrow12x=144\Rightarrow x=12\)
Chúc bạn học tốt!!!
a)
\(\left(x-3\right)\left(x^2+3x+9\right)-x\left(x+4\right)\left(x-4\right)=5\)
\(\Rightarrow x^3-3^3-x.\left(x^2-16\right)=5\)
\(\Rightarrow x^3-27-x^3+16.x=5\)
\(\Rightarrow16x-27=5\)
\(\Rightarrow16x=32\)
\(\Rightarrow x=2\)
Vậy x = 2
b)
\(\left(x-2\right)^3-\left(x+5\right)\left(x^2-5x+25\right)+6x^2=11\)
\(\Rightarrow x^3-6x^2+12x-8-x^3-125+6x^2=11\)
\(\Rightarrow12x-133=11\)
\(\Rightarrow12x=144\)
\(\Rightarrow x=12\)
Vậy x = 12
\(\left(x-2\right)^3-\left(x+5\right)\left(x^2-5x+25\right)+6x^2=11\)
=>\(x^3-6x^2+12x-8-\left(x^3+125\right)+6x^2=11\)
=>\(x^3+12x-8-x^3-125=11\)
=>12x-133=11
=>12x=144
=>\(x=\dfrac{144}{12}=12\)
a: Ta có: \(\left(x-2\right)^3-x\left(x+1\right)\left(x-1\right)+6x^2=5\)
\(\Leftrightarrow x^3-6x^2+12x-8-x^3+x+6x^2=5\)
\(\Leftrightarrow13x=13\)
hay x=1
+(x-3)2-x2=11
x2-6x+9-x2=11
-6x+9=11
-6x=2
x=2:-6
x=-1/3
(6x-3)2-36x(x-1)=40
36x2-36x+9-36x2+36x=40
9=40
=> đề sai
(2-x)2-7(x2+11)=0
4-4x+x2-7x2-77=0
-73-4x-6x2
ht bt
+) (5x-1). (2x+3)-3. (3x-1)=0
10x^2+15x-2x-3 - 9x+3=0
10x^2 +8x=0
2x(5x+4)=0
=> x=0 hoặc x= -4/5
+) x^3 (2x-3)-x^2 (4x^2-6x+2)=0
2x^4 -3x^3 -4x^4 + 6x^3 - 2x^2=0
-2x^4 + 3x^3-2x^2=0
x^2(-2x^2+x-2)=0
-2x^2(x-1)^2=0
=> x=0 hoặc x=1
+) x (x-1)-x^2+2x=5
x^2 -x -x^2+2x=5
x=5
+) 8 (x-2)-2 (3x-4)=25
8x - 16-6x+8=25
2x=33
x=33/2
a: \(\Leftrightarrow4x^2+4x+1-4x^2-16x-16=9\)
=>-12x-15=9
=>-12x=24
hay x=-2
b: \(\Leftrightarrow9x^2-6x+1+2x^2+12x+18+11\left(1-x^2\right)=6\)
\(\Leftrightarrow11x^2+6x+19+11-11x^2=6\)
=>6x+30=6
=>6x=-24
hay x=-4
c: \(\Leftrightarrow x^3+3x^2+3x+1-x^3-3x^2=2\)
=>3x=1
hay x=1/3
d: \(\Leftrightarrow x^3-6x^2+12x-8-x\left(x^2-1\right)+6x^2=5\)
\(\Leftrightarrow x^3+12x-8-x^3+x=5\)
=>13x=13
hay x=1
e: \(\Leftrightarrow x^3-27-x^3+16x=5\)
=>16x=32
hay x=2
a ) \(3\left(x-1\right)^2-3x\left(x-5\right)=1\)
\(\Leftrightarrow3\left(x^2-2.x.1+1^2\right)-3x^2+15x=1\)
\(\Leftrightarrow3x^2-2x+1-3x^2+15x=1\)
\(\Leftrightarrow13x+1=1\)
\(\Leftrightarrow13x=0\)
\(\Leftrightarrow x=0\)
Mấy bạn còn lại cũng như vậy
(x−2)3−(x+5)(x2−5x+25)+6x2=11⇔(x−2)3−(x+5)(x2−5.x+52)+6x2=11⇔x3−6x2+12x−8−(x3+53)+6x2−11=0⇔12x−144=0⇔x=12(x−2)3−(x+5)(x2−5x+25)+6x2=11⇔(x−2)3−(x+5)(x2−5.x+52)+6x2=11⇔x3−6x2+12x−8−(x3+53)+6x2−11=0⇔12x−144=0⇔x=12
Vậy x=12x=12.