Toán Lớp 8: PHÂN TÍCH ĐA THỨC THÀNH NHÂN TỬ : 16a, A=9-(x-y)^2 b, A=x^2+6x+9-y^2 c, A=x^2+4x-y^2+4 17a, A=(x-y)^2-4 b,A=9-x^2-2xy-y^2

Question

Toán Lớp 8:  PHÂN TÍCH ĐA THỨC THÀNH NHÂN TỬ : 16a, A=9-(x-y)^2      b, A=x^2+6x+9-y^2        c, A=x^2+4x-y^2+4 17a, A=(x-y)^2-4   b,A=9-x^2-2xy-y^2    c,A=x^2+4x-y^2+4  18, A=(x+y)^2-9x^2  b,A=x^2-y^2+4x+4     c,A=(x+y)^2-(x-y)^2 19, a, A=(x^2+1)^2-4x^2     b, A=x^2-2xy+y^2-1     c, A=3x^2+6xy+3y^2-3z^2 20,a, A=(3x+1)^2-(x+1)^2      b, A=x^2-xy+x-y      c, A=x^2-x+xy-3y

diemmyhoa · Answer

Giải đáp+Lời giải và giải thích chi tiết:    $ text{C&acirc;u: 16}$   a)   A=9-(x-y)^2   A=3^2-(x-y)^2   A=(3-x+y)(3+x-y)   b)   A=x^2+6x+9-y^2   A=(x^2+6x+9)-y^2   A=(x^2+2.x.3+3^2)-y^2   A=(x+3)^2-y^2   A=(x+3-y)(x+3+y)   c)   A=x^2+4x-y^2+4   A=(x^2+4x+4)-y^2   A=(x^2+2.x.2+2^2)-y^2   A=(x+2)^2-y^2   A=(x+2-y)(x+2+y)   $ text{C&acirc;u: 17}$   a)   A=(x-y)^2-4   A=(x-y)^2-2^2   A=(x-y-2)(x-y+2)   b)   A=9-x^2-2xy-y^2   A=9-(x^2+2xy+y^2)   A=3^2-(x+y)^2   A=(3-x-y)(3+x+y)   c)   A=x^2+4x-y^2+4   A=(x^2+4x+4)-y^2   A=(x^2+2.x.2+2^2)-y^2   A=(x+2)^2-y^2   A=(x+2-y)(x+2+y)   $ text{C&acirc;u: 18}$   a)   A=(x+y)^2-9x^2   A=(x+y)^2-(3x)^2   A=(x+y-3x)(x+y+3x)   A=(y-2x)(4x+y)   b)   A=x^2-y^2+4x+4   A=(x^2+4x+4)-y^2   A=(x^2+2.x.2+2^2)-y^2   A=(x+2)^2-y^2   A=(x+2-y)(x+2+y)   c)   A=(x+y)^2-(x-y)^2   A=[(x+y)-(x-y)] [(x+y)+(x-y)]   A=(x+y-x+y)(x+y+x-y)   A=2y.2x   $ text{C&acirc;u: 19}$   a)   A=(x^2+1)^2-4x^2   A=(x^2+1)^2-(2x)^2   A=(x^2+1-2x)(x^2+1+2x)   A=(x-1)^2(x+1)^2   b)   A=x^2-2xy+y^2-1   A=(x^2-2xy+y^2)-1   A=(x-y)^2-1   A=(x-y-1)(x-y+1)   c)   A=3x^2+6xy+3y^2-3z^2   A=3(x^2+2xy+y^2-z^2)   A=3[(x^2+2xy+y^2)-z^2]   A=3[(x+y)^2-z^2]   A=3(x+y-z)(x+y+z)   $ text{C&acirc;u: 20}$   a)   A=(3x+1)^2-(x+1)^2   A=[(3x+1)-(x+1)] [(3x+1)+(x+1)]   A=(3x+1-x-1)(3x+1+x+1)   A=2x(4x+2)   A=4x(2x+1)   b)   A=x^2-xy+x-y   A=(x^2-xy)+(x-y)   A=x(x-y)+(x-y)   A=(x-y)(x+1)   c)   Sửa đề : A=x^2-x+xy-3y   ->A=x^2-3x+xy-3y   A=(x^2-3x)+(xy-3y)   A=x(x-3)+y(x-3)   A=(x-3)(x+y)   ___________________________________________   &Aacute;p dụng những HĐT sau:   *(A+B)^2=A^2+2AB+B^2   *(A-B)^2=A^2-2AB+B^2   *A^2-B^2=(A-B)(A+B)   #LinhSad