Question

十字相乘法、分解因式已知多项式kx^2-6xy-8y^2可分解成（2mx+2y)(x-4y),求k、m的值注：^2指 二

Answer 1

（2mx+2y)(x-4y)

=2mx^2-8mxy+2xy-8y^2

kx^2-6xy-8y^2

所以2m=k

-8m+2=-6

m=1

k=2