5.126 5.127 5.128 (четные) заранее

5.126 7x^2-7y^2=7(x-y)(x+y)

5.127 5x(a+b)-a-b=5xa+5xb-a-b

5.128 c^3d^2-c^4d^2=c^3d^2(1-c)

Объяснение:  

  5.126

5a^2-5b^2 = 5(a^2-b^2) = 5(a-b)(a+b)      

3m^2-3n^2=3(m^2-n^2) = 3(m-n)(m+n)

a^2-a = a(a-1)          7x^2-7y^2= 7(x^2-y^2) = 7(x-y)(x+y)

b^3-b = b(b^2-1) 4m^3-4mn^2 = 4m(m^2-n^2) = 4m(m-n)(m+n)

5x^2-20y^2 = 5(x^2-4y^2) = 5(x-2y)(x+2y)

a^3b - ab^3 = ab(a^2 - b^2) = ab(a-b)(a+b)

5.127

2m(a+b)+a+b = (a+b)(2m+1)   2a(x+y) + x+y = (x+y)(2a+1)

4x(m-n)-m+n = (m-n)(4x-1)      x(a-b)+a-b = x(a+b)+(a-b) = (a+b)(x+1)

5x(a+b)-a-b = 5x(a+b)-(a+b) = (a+b)(5x-1)

4y(k-p)-k+p = 4y(k-p)-(k-p) = (k-p)(4y-1)

3m(x+y)-x-y = 3m(x+y)-(x+y) = (x+y)(3m-1)

2a(x-y)-x+y=2a(x-y)-(x-y)=(x-y)(2a-1)

5.128

xy^2+x^2y^3 = (xy^2)(1 + xy)     a^4b^2-a^2b^4 = (a^2b^2)(a^2 - b^2) =

=a^2b^2(a-b)(a+b)

m^2n^2 - mn^3 = (mn^2)(m-n)    a^3b^2 + a^5b^3 = (a^3b^2)(1 + a^2b)

c^3d^2 - c^4d^2 = (c^3d^2)(1 - c^2)    

-x^5y^3 - x^3y^5 = (-x^3y^3)(x^2+y^2)

Могут быть ошибки) я не мега-мозг))