Phân tích đa thức thành nhân tử : a)14x³y⁴-21x²y³ b)12x³y⁴-4x²y³ c)5a²-5ab+7a-7b d)6xy-2y²+15x-5y
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a) 15x + 15y = 15(x + y)
b) 6x - 10y = 2(3x - 5y)
c) 2a + 4b - 6c = 2(a + 2b - 3c)
d) 6xy - 12x - 18y = 6(xy - 2x - 3y)
e) 2(x + y) - 5a(x + y) = (2 - 5a)(x + y)
f) 6x(x - y) + 5(y - x) = 6x(x - y) + (-5)(x - y) = (6x - 5)(x - y)
a) \(15x+15y=15\left(x+y\right)\)
b) \(6x-10y=2\left(3x-5y\right)\)
c) \(2a+4b-6c=2\left(a+2b-3c\right)\)
d) \(6xy-12x-18y=6\left(xy-2x-3y\right)\)
e) \(2\left(x+y\right)-5a\left(x+y\right)=\left(2-5a\right)\left(x+y\right)\)
f) \(6x\left(x-y\right)+5\left(y-x\right)=6x\left(x-y\right)-5\left(x-y\right)=\left(6x-5\right)\left(x-y\right)\)
a) Xem lại đề
b) x³ - 4x²y + 4xy² - 9x
= x(x² - 4xy + 4y² - 9)
= x[(x² - 4xy + 4y² - 3²]
= x[(x - 2y)² - 3²]
= x(x - 2y - 3)(x - 2y + 3)
c) x³ - y³ + x - y
= (x³ - y³) + (x - y)
= (x - y)(x² + xy + y²) + (x - y)
= (x - y)(x² + xy + y² + 1)
d) 4x² - 4xy + 2x - y + y²
= (4x² - 4xy + y²) + (2x - y)
= (2x - y)² + (2x - y)
= (2x - y)(2x - y + 1)
e) 9x² - 3x + 2y - 4y²
= (9x² - 4y²) - (3x - 2y)
= (3x - 2y)(3x + 2y) - (3x - 2y)
= (3x - 2y)(3x + 2y - 1)
f) 3x² - 6xy + 3y² - 5x + 5y
= (3x² - 6xy + 3y²) - (5x - 5y)
= 3(x² - 2xy + y²) - 5(x - y)
= 3(x - y)² - 5(x - y)
= (x - y)[(3(x - y) - 5]
= (x - y)(3x - 3y - 5)
\(1-2y+y^2=\left(y-1\right)^2\)
\(\left(x+1\right)^2-25=\left(x-1\right)^2-5^2=\left(x-6\right)\left(x+4\right)\)
\(1-4x^2=1-\left(2x\right)^2=\left(1-2x\right)\left(1+2x\right)\)
\(8-27x^3=\left(2-3x\right)\left(4+6x+9x^2\right)\)
\(27+27x+9x^2+x^3=\left(x+3\right)^3\)
\(8x^3-12x^2y+6xy^2-y^3=\left(2x-y\right)^3\)
\(x^3+8y^3=\left(x+2y\right)\left(x^2-2xy+4y^2\right)\)
Tham khảo nhé~
Mấy cái này chỉ áp dụng HĐT thoyy nha!
\(a,1-2y+y^2=\left(1-y\right)^2\)
\(b,\left(x-1\right)^2-25=\left(x-1-5\right)\left(x-1+5\right)=\left(x-6\right)\left(x+4\right)\)
\(c,1-4x^2=\left(1-2x\right)\left(1+2x\right)\)
\(d,8-27x^3=\left(2-3x\right)\left(4+6x+9x^2\right)\)
\(e,27+27x+9x^2+x^3=\left(x+3\right)^3\)
\(f,8x^3-12x^2y+9xy^2-y^3=\left(2x-y\right)^2\)
\(g,x^3+8y^3=\left(x+2y\right)\left(x^2-2xy+y^2\right)=\left(x+2y\right)\left(x-y\right)^2\)
=.= hok tốt!!
\(\left(x-1\right)^2-25\)
\(=x^2-2x+1-25\)
\(=x^2-2x-24\)
\(=x^2-6x+4x-24\)
\(=x.\left(x-6\right)+4.\left(x-6\right)\)
\(=\left(x+4\right).\left(x-6\right)\)
a, \(1-2y+y^2=\left(y+1\right)^2=\left(y+1\right)\left(y+1\right)\)
b, \(\left(x+1\right)^2-25=\left(x+1\right)^2-5^2=\left(x+1-5\right)\left(x+1+5\right)=\left(x-4\right)\left(x+6\right)\)
c, \(1-4x^2=1^2-\left(2x\right)^2=\left(1-2x\right)\left(1+2x\right)\)
d, \(8-27x^3=2^3-\left(3x\right)^3=\left(2-3x\right)\left(4+6x+9x^2\right)\)
Lời giải:
a. $A=9x^2+15x+6xy+y^2+5y=(9x^2+6xy+y^2)+(15x+5y)$
$=(3x+y)^2+5(3x+y)=0^2+5.0=0$
b. $25x^2-y^4-5x+y^2=(25x^2-y^4)-(5x-y^2)=(5x-y^2)(5x+y^2)-(5x-y^2)$
$=(5x-y^2)(5x+y^2-1)$
Bài làm:
a, 1-4x2
=1-(2x)2
=(1-2x).(1+2x)
b, 8-27x3
=23-(3x)3
=(2-3x).(4+6x+9x2)
Các câu còn lại bạn dùng hằng đẳng thức là phân tích được ra thôi
1 - 4x^2
= 1^2 - ( 2x )^2
= ( 1 - 2x ) ( 1 + 2x )
8 - 27x^ 3
= 2^3 - ( 3x )^3
= ( 2 - 3x ) [ 2^2 + 2 * 3x + ( 3x )^2 ]
= ( 2 - 3x ) ( 4 + 6x + 9x^2 )
= ( 2 - 3x ) ( 9x^2 + 6x + 4 )
27 + 27x + 9x^2 + x^3
= x^3 + 9x^2 + 27x + 27
= x^3 + 3x^2 + 6x^2 + 18x + 9x + 27
= x^2 ( x + 3 ) + 6x ( x + 3 ) + 9 ( x + 3 )
= ( x + 3 ) ( x^2 + 6x + 9 )
= ( x + 3 ) ( x + 3 )^2
= ( x + 3 )^3
x^2 + 4x - 5
= x^2 - x + 5x - 5
= x ( x - 1 ) + 5 ( x - 1 )
= ( x + 1 ) ( x - 5 )
c: =5a(a-b)+7(a-b)
=(a-b)(5a+7)