1,
A) a^2 + 3a
B) 14a + 21b
C) a(x+y) + B (x+y)
2)
A) (a – 3b)^2 – 16c^2
B) 6 (x-y)^2 – 25 ( x + y)^2
3)
A) x^8 + x^4 +1
4)
2x^2 + 10x + 8
1,
A) a^2 + 3a
B) 14a + 21b
C) a(x+y) + B (x+y)
2)
A) (a – 3b)^2 – 16c^2
B) 6 (x-y)^2 – 25 ( x + y)^2
3)
A) x^8 + x^4 +1
4)
2x^2 + 10x + 8
1.
A) a² + 3a = a(a+3)
B) 14a + 21b = 7(2a + 3b)
C) a(x+y) + b (x+y) = (x+y) (a+b)
2.
A) (a – 3b)² – 16c² = (a – 3b)² – (4c)² = (a-3b-4c) (a-3b+4c)
B) 6 (x-y)² – 25 ( x + y)²
=[ 4 (x-y) ]²- [ 5 (x+y) ]²
=(4x-4y) ² – (5x+5y) ²
=(4x-4y+5x+5y)(4x-4y-5x-5y)
=(9x+y)(−x−9y)
3. A) x^8 + x^4 +1 = (x^4)² + 2x^4 + 1 – x^4
= (x^4 + 1)² – (x²)²
= (x^4+1-x²) (x^4+1+x²)
4) 2x² + 10x + 8 = 2x² + 2x + 8x + 8
= 2x(x+1) + 8(x+1)
= (x+1) ( 2x+8)
NHỚ VOTE 5 SAO VÀ CTLHN CHO MIK NHÉ. THANKS!
Đáp án:
Giải thích các bước giải:
1)
a/ `a^2+3a=a(a+3)`
b) `14a+21b=7(2a+3b)`
c) `a(x+y)+b(x+y)=(a+b)(x+y)`
2/
a) `(a-3b)^2-16c^2`
`=(a-3b+16c)(a-3b-16c)`
b) `16(x-y)^2-25(x+y)^2`
`=[4(x-y)]^2-[5(x+y)]^2`
`=(4x-4y)^2-(5x+5y)^2`
`=(4x-4y+5x+5y)(4x-4y-5x-5y)`
`=(9x+y)(-x-9y)`
3)
\( a)x^8+x^4+1\\ =\left(x^8+2x^4+1\right)-x^4\\ =\left(x^4+1\right)^2-x^4\\ =\left(x^4-x^2+1\right)\left(x^4+x^2+1\right)\)
4)
`2x^2+10x+8`
`=2x^2+2x+8x+8`
`=2x(x+1)+8(x+1)`
`=(2x+8)(x+1)`