Question

phan tích đa thức sau thành nhân tử

-x^2-2x+15

Answer 1

\(-x^2-2x+15=-\left(x^2+2x-15\right)\)

\(=-\left[\left(x^2-3x\right)+\left(5x-15\right)\right]\)

\(=-\left[x\left(x-3\right)+5\left(x-3\right)\right]\)

\(=-\left(x-3\right)\left(x+5\right)\)

Answer 2

Ta có: -x^2-2x+15 = -x^2-5x+3x+15 = -x(x+5)+3(x+5) = (3-x)(x+5).
Hok tốt ~~~

Answer 3

-x² - 2x + 15

= -x² + 3x - 5x + 15

= ( 3x - x² ) + ( 15 - 5x )

= x( 3 - x ) + 5( 3 - x )

= ( 3 - x )( x + 5 )

Answer 4

\(-x^2-2x+15\) 

\(=-x^2-5x+3x+15\) 

\(=-x\left(x+5\right)+3\left(x+5\right)\) 

\(=\left(3-x\right)\left(x+5\right)\)

Answer 5

         Bài làm :

Ta có :

-x² - 2x + 15

= -x² + 3x - 5x + 15

= ( 3x - x² ) + ( 15 - 5x )

= x( 3 - x ) + 5( 3 - x )

= ( 3 - x )( x + 5 )

Answer 6

\(-x^2-2x+15\)

\(=-x^2+3x-5x+15\)

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

\(=x\left(3-x\right)-5\left(x-3\right)\)

\(=x\left(3-x\right)+5\left(3-x\right)\)

\(=\left(3-x\right)\left(x+5\right)\)