Jawapan

2015-04-04T22:42:14+08:00
= 4x^2 + 6xy - 6xy -9y^2 - 4x^2
= -9y^2

note : ^ = kuasa
2015-04-05T10:11:47+08:00
4x²+6xy-6xy-9y²-4x²
=4x²-4x²+6xy-6xy-9y²
=-9y²