Đáp án:
Bài 1:
a,(2x-5)(4x-3x)-(3x+11)(5-2x)-15.(2x-5)
<=>(2x-5)x+(3x+11)(2x-5)-15.(2x-5)
<=>(2x-5).(x+3x+11-15)
<=>(2x-5).(4x-4)
b,(x²-2x+3)(3x-5)-(x²+x-1).(2x+7)
<=>(3x³-5x²-6x²+10x+9x-15)-(2x³+7x²-2x²+7x-2x-7)
<=>3x³-11x²+19x-15-2x³-7x²+2x²-7x+2x+7
<=>x³-16x²+14x-8
Chúc bạn học tốt!