a) x^2+4x+4=
b) x^2-8x+16=
c) (x+5).(x-5)=
d) x^2+2x+1=
e) x^2-1=
f) x^2+6x+9=
g) 4x^2-9=
h) 16x^2-8x+1=
i) 9x^2+6x+1=
k) 36x^2+36x+9=
a) x^2+4x+4=
b) x^2-8x+16=
c) (x+5).(x-5)=
d) x^2+2x+1=
e) x^2-1=
f) x^2+6x+9=
g) 4x^2-9=
h) 16x^2-8x+1=
i) 9x^2+6x+1=
k) 36x^2+36x+9=
a) x² + 4x + 4
= x² + 2.2x + 2²
= (x + 2)²
b) x² – 8x + 16
= x² – 2.4x + 4²
= (x – 4)²
c) (x + 5)(x – 5)
= x² – 5x + 5x – 25
= x² – 25
d) x² + 2x + 1
= (x + 1)²
e) x² – 1
= (x – 1)(x + 1)
f) x² + 6x + 9
= x² + 2.3x + 3²
= (x + 3)²
g) 4x² – 9
= (2x)² – 3²
= (2x – 3)(2x + 3)
h) 16x² – 8x + 1
= (4x)² – 2.4x + 1
= (4x – 1)²
i) 9x² + 6x + 1
= (3x)² + 2.3x + 1
= (3x + 1)²
k) 36x² + 36x + 9
= (6x)² + 2.3.6x + 3²
= (6x + 3)²
Đáp án:
a) x² + 4x + 4
= x² + 2.2x + 2²
=(x + 2)²
b) x² – 8x + 16
= x² – 2.4x + 4²
=(x – 4)²
c) (x + 5).(x – 5)
=x² -5²
= x² -25
d) x² + 2x + 1
= (x + 1)²
e) x² – 1
= (x – 1 )(x + 1)
f) x² + 6x + 9
= x² + 2.3x + 3²
=(x + 3)²
g) 4x² – 9
= (2x)² – 3²
=(2x – 3)(2x +3)
h) 16x² – 8x + 1
= (4x²) – 2.4x +1
=(4x -1)²
i) 9x² + 6x + 1
=(3x)² + 2.3x +1
= (3x + 1)²
k) 36x² + 36x + 9
= (6x)² + 2.3.6x + 3²
= (6x + 3)²