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a) x2+20x+*
=> x2 +2 x 5x2+52
= (x+5)2
b) 16x2+24xy+*
=> (4x)2+2 x 4x x 3+32
= (4x + 3)2
c) y2 -*+49
=> y2 - 2y72+72
= (y-7)2
d) * - 42xy + 49y2
= (3x)2 + 2 x 7y3x + (7y)2
= (3x+7y)2
`a)x^2+20x+100=(x+10)^2`
`b)16x^2+24xy+9y^2=(4x+3y)^2`
`c)y^2-14y+49=(y-7)^2`
`d)9x^2-42xy+49y^2=(3x-7y)^2`
a, \(x^2+2x.10+100=\left(x+10\right)^2\)
\(b,16x^2+2.4x.3y+9y^2=\left(4x+3y\right)^2\)
\(c,y^2-14y+49=\left(y-7\right)^2\)
\(d,9x^2-2.3x.7x+49y^2=\left(3x-7y\right)^2\)
\(x^2+20x+100=\left(x+10\right)^2\)
\(16x^2+24xy+\left(3y\right)^2=\left(4x+3y\right)^2\)
\(y^2-14y+49=\left(y-7\right)^2\)
\(a,\) \(x^2+20x+100=\left(x+10\right)^2\)
\(b,\) \(16x^2+24x+9=\left(4x+3\right)^2\)
\(c,\) \(y^2-14x+49=\left(y-7\right)^2\)
a) x2+20x+* = \(x^2+2.x.10+10^2=\left(x+10\right)^2\)
b) \(y^2-2.y.7+7^2=y^2-14y+49=\left(y-7\right)^2\)
a) \(x^2+20x+100=\left(x+10\right)^2\)
b) \(y^2-14y+49=\left(y-7\right)^2\)
p/s: chúc bn học tốt
a ) ( 2x + 1 )2 - 4 ( x + 2 )2 = 9
4x2 + 4x + 1 - 4 ( x2 +4x + 4 ) = 9
4x2 + 4x + 1 - 4x2 -16x -16 = 9
-12x - 15 = 9
-12x = 24
x = -2
b) 3 ( x - 1 )2 - 3x ( x - 5 ) = 1
3 ( x2 - 2x + 1 ) - 3x2 + 15x = 1
3x2 - 6x + 3 - 3x2 + 15x = 1
9x + 3 = 1
9x = -2
x = \(\frac{-2}{9}\)
a) x2 + 20x + *
= x2 + 2.x.10 + 102
= x2 + 20x + 100
b) 16x2 + 24xy +*
= 16x2 +2.x.12y + (12y)2
= 16x2 +24xy + 144y2
c) y2 - * + 49
= y2 - * +72
= y2 - 2.y.7 + 49
= y2 - 14y + 49
d) * - 42xy + 49y2
= * - 42xy + (7y)2
= * - 2.3x.7y + (7y)2
= (3x)2 - 42xy + (7y)2
= 9x2 - 42xy + 49y2