Tìm x:
a)\(\left\{\left[\left(2x+14\right):2^2-3\right]:2\right\}-1=0\)
b) \(10-\left\{\left[\left(x:3+17\right):10+3:2^4\right]:10\right\}=5\)
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a: =>8x^2-20x+20x-50+4x(4x^2-12x+9)=0
=>8x^2-50+8x^3-48x^2+36x=0
=>8x^3-40x^2+36x-50=0
=>\(x\simeq4,29\)
b: =>(2x-3-3x-1)(2x-3+3x+1)=0
=>(-x-4)(5x-2)=0
=>x=2/5 hoặc x=-4
a) \(\left\{\left[\left(2x+14\right)\div2^2-3\right]\div2\right\}-1=0\)
\(\left[\left(2x+14\right)\div4-3\right]\div2=0+1\)
\(\left[\left(2x+14\right)\div4-3\right]=\left(0+1\right).2\)
\(\left(2x+14\right)\div4=\left(0+1\right).2+3\)
\(\left(2x+14\right)\div4=5\)
\(2x+14=5.4\)
\(2x+14=20\)
\(2x=20-14\)
\(2x=6\)
\(x=6\div2\)
\(x=3\)
b) Làm tương tự phần a)
a){[(2x+14)/22-3]/2}-1=0
{[(2x+14)/4-3]/2}-1 =0
[(2x+14)/4-3]/2 =0+1
[(2x+14)/4-3]/2 =1
(2x+14)/4-3 =1*2
(2x+14)/4-3 =2
(2x+14)/4 =2+3
(2x+14)/4 =5
2x+14 =5*4
2x+14 =20
2x =20-14
2x =6
x =6/2
x =3
gio minh dang ban nen chi giai phan a thoi nhe, khi nao ranh minh se giai not phan con lai sau nhe
b)(2x - 1)^2 - (2x + 5) (2x - 5 ) = 18
4x 2 -4x+1-4x 2+25=18
26-4x=18
4x=8
x=2
a,27x-18=2x-3x^2
<=> 3x^2-2x+27-18x=0
<=> 3x^2-20x+27=0
\(\Delta\)= 20^2-4-12.27
tính \(\Delta\)rồi tìm x1 ,x2
1) (x - 2)2 - (x - 3)(x + 3) = 17
=> x2 - 4x + 4 - x2 + 9 = 17
=> -4x = 17 - 13
=> -4x = 4
=> x = -1
2) TTT
3) x2 + 6x - 147 = 0
=> x2 + 19x - 13x - 147 = 0
=> x(x + 19) - 13(x + 19) = 0
=> (x - 13)(x + 19) = 0
=> \(\orbr{\begin{cases}x-13=0\\x+19=0\end{cases}}\)
=> \(\orbr{\begin{cases}x=13\\x=-19\end{cases}}\)
4) (3x - 5)(2x + 3) - 6x2 = 7
=> 6x2 + 9x - 10x - 15 - 6x2 = 7
=> -x - 15 = 7
=> -x = 7 + 15
=> -x = 22
=> x = -22
5) TL
\(b,\left(x+2\right)\left(x^2-2x+4\right)-x\left(x^2+2\right)=15\)
\(\Leftrightarrow x^3+8-x^3-2x=15\)
\(\Leftrightarrow-2x=15-8=7\)
\(\Leftrightarrow x=\frac{-7}{2}\)
Vậy \(x=\frac{-7}{2}\)
e) Ta có: \(2\left|x-\dfrac{1}{2}\right|\ge0\forall x\)
\(\Leftrightarrow2\left|x-\dfrac{1}{2}\right|+2021\ge2021\forall x\)
Dấu '=' xảy ra khi \(x=\dfrac{1}{2}\)
10 - { [ ( x : 3 + 17 ) : 10 + 3 : 24 ] : 10 } = 5
[ ( x : 3 + 17 ) : 10 + 3 : 24 ] : 10 = 10 - 5 = 5
( x : 3 + 17 ) : 10 + 3 : 24 = 5 x 10
( x : 3 + 17 ) : 10 + 48 = 50
( x : 3 + 17 ) : 10 = 50 - 48
( x : 3 + 17 ) : 10 = 2
x : 3 + 17 = 2 x 10
x : 3 + 17 = 20
x : 3 = 20 - 17 = 3
x = 3 x 3 = 9
a) [(2x+14) : 4 - 3] : 2 = 1
(2x+14) : 4 - 3 = 1/2
(2x+14) : 4 = 1/2 + 3
(2x+14) : 4 = 7/2
2x+14 = 7/2 . 1/4
2x = 7/8 - 1/4
2x = 5/8
x= 5/8.1/2
x= 5/16