Giải phương trình bằng phương phác tách hạng tử :
( 4x + 3 ) ^2 - ( 4x - 3 ) ^ 2 = 5x+ 2
giúp em nhanh nhé 😘😘
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1) x2 - 4x + 3
= x2 - x - 3x + 3
= (x2 - x) - (3x - 3)
= x.(x - 1) - 3.(x - 1)
= (x - 1).(x - 3)
2) x2 - x - 6
= x2 + 2x - 3x - 6
= (x2 + 2x) - (3x + 6)
= x.(x + 2) - 3.(x + 2)
= (x + 2).(x - 3)
3) x2 + 5x + 4
= x2 + x + 4x + x
= (x2 + x) + (4x + x)
= x.(x + 1) + 4.(x + 1)
= (x + 1).(x + 4)
4) x2 + 5x + 6
= x2 + 2x + 3x + 6
= (x2 + 2x) + (3x + 6)
= x.(x + 2) + 3.(x + 2)
= (x + 2).(x + 3)
a,=x^2+x+3x+3
=x(x+1)+3(x+1)
=(x+3)(x+1)
b,x^2-3x+2x-6
=x(x-3)+2(x-3)
=(x+2)(x-3)
2 câu còn lại từ lm nha.........
a) \(x^3+4x^2-21x\)
\(=x\left(x^2+4x-21\right)\)
\(=x\left(x^2-3x+7x-21\right)\)
\(=x\left[x\left(x-3\right)+7\left(x-3\right)\right]\)
\(=x\left(x-3\right)\left(x+7\right)\)
b) \(5x^3+6x^2+x\)
\(=x\left(5x^2+6x+1\right)\)
\(=x\left(5x^2+5x+x+1\right)\)
\(=x\left[5x\left(x+1\right)+\left(x+1\right)\right]\)
\(=x\left(x+1\right)\left(5x+1\right)\)
c) \(x^3-7x+6\)
\(=x^3+2x^2-3x-2x^2-4x+6\)
\(=x\left(x^2+2x-3\right)-2\left(x^2+2x-3\right)\)
\(=\left(x-2\right)\left(x^2+2x-3\right)\)
\(=\left(x-2\right)\left(x-1\right)\left(x+3\right)\)
d) \(3x^3+2x-5\)
\(=3x^3+3x^2+5x-3x^2-3x-5\)
\(=x\left(3x^2+3x+5\right)-\left(3x^2+3x+5\right)\)
\(=\left(x-1\right)\left(3x^2+3x+5\right)\)
Làm 1 cách là đủ rồi mà (: 6 cách thì đến bao giờ :v
a) x2 + x - 6 = x2 - 2x + 3x - 6 = x( x - 2 ) + 3( x - 2 ) = ( x - 2 )( x + 3 )
b) x2 - 4x + 3 = x2 - x - 3x + 3 = x( x - 1 ) - 3( x - 1 ) = ( x - 1 )( x - 3 )
c) x2 + 5x + 4 = x2 + x + 4x + 4 = x( x + 1 ) + 4( x + 1 ) = ( x + 1 )( x + 4 )
d) x2 - x - 6 = x2 + 2x - 3x - 6 = x( x + 2 ) - 3( x + 2 ) = ( x + 2 )( x - 3 )
e) 2x2 + 5x + 3 = 2x2 + 2x + 3x + 3 = 2x( x + 1 ) + 3( x + 1 ) = ( x + 1 )( 2x + 3 )
g) 2x2 - 7x + 3 = 2x2 - 6x - x + 3 = 2x( x - 3 ) - ( x - 3 ) = ( x - 3 )( 2x - 1 )
h) 3x2 + 10x - 8 = 3x2 + 12x - 2x - 8 = 3x( x + 4 ) - 2( x + 4 ) = ( x + 4 )( 3x - 2 )
k) \(\frac{1}{2}x^2-\frac{19}{6}x+1=\frac{1}{2}x^2-\frac{1}{6}x-3x+1=\frac{1}{2}x\left(x-\frac{1}{3}\right)-3\left(x-\frac{1}{3}\right)=\left(x-\frac{1}{3}\right)\left(\frac{1}{2}x-3\right)\)
7(x - 3) - x(3 - x)
= (x - 3)(7 + x)
chỉ bt có v mà k bt có đúng k
1 ) 7 ( x - 3 ) - x ( 3 - x )
= 7 ( x - 3 ) + x ( x - 3 )
= ( x - 3 ) ( 7 + x )
2 ) 4x2 - 6x + 3 - 2x
= 4x2 - 2x - 6x + 3
= 2x ( 2x - 1 ) - 3 ( 2x - 1 )
= ( 2x - 1 ) ( 2x - 3 )
3 ) ( 4 - x ) - 4x + x2
= ( 4 - x ) - x ( 4 - x )
= ( 4 - x ) ( 1 - x )
4 ) x2 - 2xy + y2
= ( x - y )2
4x - 15 = 32.5
4x - 15 = 310
4x = 310 + 15
4x = 59064
x = 59064 : 4
x = 14766
a. \(=4x^3-12x^2-x^2+3x+6x-18=\left(x-3\right)\left(4x^2-x+6\right)\)
b. \(=-x^3+x^2-7x^2+7x-x+1=\left(x-1\right)\left(-x^2-7x-1\right)\)
c. \(=x^3+2x^2-6x^2-12x+4x+8=\left(x+2\right)\left(x^2-6x+4\right)\)
(4x + 3)2 - (4x - 3)2 = 5x + 2
16x2 + 2.4x.3 + 9 - (16x2 - 2.4x.3 + 9) = 5x + 2
16x2 + 2.4x.3 + 9 - 16x2 + 2.4x.3 - 9 = 5x + 2
48x = 5x + 2
43x = 2
\(x=\frac{2}{43}\)