Question

1) phân tích đa thức thành nhân tư:

A) (ab-1)^2 + ( a +b)^2

B) x^2 -13x +36

C) 3x^2 - 16x +5

Answer 1

a) ( ab - 1 )² + ( a + b )²

= a²b² - 2ab + 1 + a² + 2ab + b²

=a²b² + a² + b² + 1

b) x² - 13x + 36

= x² - 4x - 9x + 36

= ( x² - 4x ) - ( 9x - 36 )

= x ( x - 4 ) - 9 ( x - 4 )

= ( x - 4 )( x - 9 )

c) 3x² - 16x + 5

= 3x² - x - 15x + 5

= ( 3x² - x ) - ( 15x - 5 )

= x ( 3x - 1 ) - 5 ( 3x - 1 )

= ( 3x - 1 )( x - 5 )

Hk tốt

Answer 2

A)\(\left(ab-1\right)^2+\left(a+b\right)^2=\left(ab\right)^2-2ab+1+a^2+2ab+b^2=a^2b^2+a^2+b^2+1\)

B)\(x^2-13x+36=x^2-4x-9x+36=x\left(x-4\right)-9\left(x-4\right)=\left(x-9\right)\left(x-4\right)\)

C)\(3x^2-16x+5=3x^2-x-15x+5=x\left(3x-1\right)-5\left(3x-1\right)=\left(x-5\right)\left(3x-1\right)\)