(3x + 2 )2 - ( 3x-2 )2 = 5x + 38
ĐS: 2
TH
Những câu hỏi liên quan
a, (3x+2)2 - (3x-2)2 =5x+38 b, 3(x-2)2 +9(x-1) =3(x2+x-3)
a: =>9x^2+12x+4-9x^2+12x-4=5x+38
=>24x=5x+38
=>19x=38
=>x=2
b: =>3x^2-12x+12+9x-9=3x^2+3x-9
=>-3x+3=3x-9
=>-6x=-12
=>x=2
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C1: Giải phương trình:
a) (3x+2)^2 - (3x-2)^2 = 5x + 38
b) (x+1) (x^2-2x+1) - 2x = 2(x-1)(x+1)
c) 3(x-2)^2 + 9(x-1) = 3(x^2+x-3)
e) (x-1)^3 - x(x+1)^2 = 5x + 38
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a) \(\left(3x+2\right)^2-\left(3x-2\right)^2=5x+38\)
\(\Leftrightarrow\left[\left(3x+2\right)-\left(3x-2\right)\right]\left[\left(3x+2\right)+\left(3x-2\right)\right]=5x+38\)
\(\Leftrightarrow\left(3x+2-3x+2\right)\left(3x+2+3x-2\right)=5x+38\)
\(\Leftrightarrow4\cdot6x=5x+38\)
\(\Leftrightarrow24x-5x=38\)
\(\Leftrightarrow19x=38\Leftrightarrow x=\dfrac{38}{19}=2\)
Vậy \(S=\left\{2\right\}\)
b) \(\left(x+1\right)\left(x^2-2x+1\right)-2x=2\left(x-1\right)\left(x+1\right)\)
\(\Leftrightarrow x^3-2x^2+x+x^2-2x+1-2x=2\left(x^2-1\right)\)
\(\Leftrightarrow x^3-2x^2+x+x^2-2x+1-2x=2x^2-2\)
\(\Leftrightarrow x^3-2x^2+x+x^2-2x+1-2x-2x^2+2=0\)
\(\Leftrightarrow x^3-3x^2-3x+3=0\)
PT vô nghiệm , không tìm được x
Vậy \(S=\varnothing\)
c) \(3\left(x-2\right)^2+9\left(x-1\right)=3\left(x^2+x-3\right)\)
\(\Leftrightarrow3\left(x^2-2x+4\right)+9\left(x-1\right)=3\left(x^2+x-3\right)\)
\(\Leftrightarrow3x^2-6x+12+9x-9=3x^2+3x-9\)
\(\Leftrightarrow3x^2-6x+12+9x-9-3x^2-3x+9=0\)
\(\Leftrightarrow0x+12=0\)
PT vô nghiệm
Vậy \(S=\varnothing\)
Câu cuối tương tự
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C1: Giải phương trình:
a) (3x+2)^2 - (3x-2)^2 = 5x + 38
b) (x+1) (x^2-2x+1) - 2x = 2(x-1)(x+1)
c) 3(x-2)^2 + 9(x-1) = 3(x^2+x-3)
e) (x-1)^3 - x(x+1)^2 = 5x + 38 plz
Xem chi tiết
C1: Giải phương trình:
a) (3x+2)^2 - (3x-2)^2 = 5x + 38
b) (x+1) (x^2-2x+1) - 2x = 2(x-1)(x+1)
c) 3(x-2)^2 + 9(x-1) = 3(x^2+x-3)
e) (x-1)^3 - x(x+1)^2 = 5x + 38 plz
Xem chi tiết
a) ( 3x + 2 )2 - ( 3x - 2 )2 = 5x + 38
\(\left(3x+2\right)^2-\left(3x-2\right)^2=5x+38\)
\(\Leftrightarrow9x^2+12x+4-9x^2+12x-4=5x+38\)
\(\Leftrightarrow24x-5x-38=0\)
\(\Leftrightarrow19x-38=0\)
\(\Leftrightarrow19\left(x-2\right)=0\)
\(\Leftrightarrow x-2=0\)
\(\Leftrightarrow x=2\)
VẬY ..
Đáp án:
\(S=\left\{2\right\}\)
Lời giải:
a) \(\left(3x+2\right)^2-\left(3x-2\right)^2=5x+38\)
\(\Leftrightarrow\left[\left(3x+2\right)-\left(3x-2\right)\right].\left(3x+2+3x-2\right)=5x+38\)
\(\Leftrightarrow\left(3x+2-3x+2\right).6x=5x+38\)
\(\Leftrightarrow24x=5x+38\)
\(\Leftrightarrow24x-5x=38\)
\(\Leftrightarrow19x=38\)
\(\Leftrightarrow x=2\)
Vậy phương trình có tập nghiệm là \(S=\left\{2\right\}\)
a, (3x+2)2 - (3x-2)2 =5x+38 b, 3(x-2)2 +9(x-1) =3(x2+x-3)
c, (x+3)3 -(x-3)2 -(x-3)2 =6x+18 d, (x-1)3-x(x+1)2=5x(2-x)-11(x+2)
e, (x+1)(x2-x+1)-2x=x(x-1)(x+1) f, (x-2)3+(3x-1)(3x+1)=(x+1)3
a: =>9x^2+12x+4-9x^2+12x-4=5x+38
=>24x=5x+38
=>19x=38
=>x=2
e: =>x^3+1-2x=x^3-x
=>-2x+1=-x
=>-x=-1
=>x=1
f: =>x^3-6x^2+12x-8+9x^2-1=x^3+3x^2+3x+1
=>12x-9=3x+1
=>9x=10
=>x=10/9
b: \(\Leftrightarrow3x^2-12x+12+9x-9=3x^2+3x-9\)
=>-3x+3=3x-9
=>-6x=-12
=>x=2
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a) ( 3x + 2 )2 - ( x - 3 )2 = 5x + 38
\(\left(3x+2\right)^2-\left(x-3\right)^2=5x+8\)
\(\Leftrightarrow\left(3x+2+x-3\right)\left(3x+2-x+3\right)=5x+8\)
\(\Leftrightarrow\left(4x-1\right)\left(2x+5\right)=5x+8\)
\(\Leftrightarrow8x^2+18x-5=5x+8\)
\(\Leftrightarrow8x^2+13x-13=0\)
Ta có \(\Delta=13^2+4.8.13=585,\sqrt{\Delta}=3\sqrt{65}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{-13+3\sqrt{65}}{16}\\x=\frac{-3-3\sqrt{65}}{16}\end{cases}}\)
(3x+2)^2-(3x-2)^2=5x+38
Làm nhanh hộ mình cảm ơn
Mai mình nộp rồi
^2 là mũ 2 nha
\(\left(3x+2\right)^2-\left(3x-2\right)^2=5x+38\)
\(\Leftrightarrow\left(9x^2+12x+4\right)-\left(9x^2-12x+4\right)=5x+38\)
\(\Leftrightarrow24x=5x+38\Leftrightarrow19x=38\Leftrightarrow x=\frac{38}{19}=2\)
Vậy $x=2$
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(3x+2)2-(3x-2)2=5x+38
⇒(3x+2-3x+2)(3x+2+3x-2)=5x+38
⇒4.6x=5x+38
⇒19x=38
⇒x=2
Vậy...
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Giải các phương trình sau:
a) 4x – 6 = 4 - 2(x+5)
b)x( x – 2) – x(x + 3) = 24
c) 2(x + 4) – 3(x – 2) = 5
d) x2 + 2x – 15 = 0
đ) 10x2 – 5x = 0
e)(3x + 2)2 – (3x – 2)2 = 5x + 38
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