Question

因式分解(十字相乘法)

填空:
(1)2x立方-13x平方-24x=__________
(2)2a平方b平方+19ab-60=_________
因式分解(要步骤)
(1)3x平方-7x+4
(2)-10x平方z+25xyz-15y平方z
(3)x平方+(k+2)x+(k+1)
(4)6x平方-5xy-4y平方
(5)8x平方y平方-23xy+14
(6)28n平方+58n-30

Answer 1

填空

(1)2x³-13x²-24x = x(x(2x-13)-24)

(2)2a²b²+19ab-60 = ab(2ab+19)-60

因式分解

(1)3x²-7x+4 = x(3x-7)+4

(2)-10x²z+25xyz-15y²z =5z(5xy-2x²-3y²)=5xyz(5-2x/y-3y/x)

(3)x²+(k+2)x+(k+1) = x*x+kx+2x+k+1=(x+1)(x+1+k)

(4)6x²-5xy-4y² = xy(6x/y-4y/x-5)

(5)8x²y²-23xy+14 =xy(8xy-23)+14 

(6)28n²+58n-30 = 2(n(14n+29)-15)

Answer 2