Question

已知A=2x-3，B=-3x+5.计算: (1)3A(-2B); (2)(5A+B) (2A-3B

已知A=2x-3，B=-3x+5.计算:
(1)3A(-2B);
(2)(5A+B) (2A-3B)

Answer 1

1。因为 A=2x-3, B=3X+5,
所以 （1）3A(-2B)=3(2x-3)X[-2(-3x+5)]
=(6x-9)(6x-10)
=36x^2-60x-54x+90
=36x^2-114x+90。
（2）(5A+B)(2A-3B)=[5(2x-3)+(-3x+5)][2(2x-3)-3(-3x+5)]
=(10x-15-3x+5)(4x-6+9x-15)
=(7x-10)(13x-21)
=91x^2-130x-147x+210
=91x^2-277x+210。
3。(a-3)(a^2+2)+(-a+3)(2a2-3)
=(a-3)(5-a^2)。

Answer 2

1.3A(-2B)
=3(2X-3)[-2(-3X+5)]
=-6(-6X²+X-15)
=36X²-6X+90
2.(5A+B)(2A-3B)
=[5(2X-3)-3X+5][2(2X-3)-3(-3X+5)]
=(10X-15-3X+5)(4X-6+9X-15)
=(7X-10)(13X-21)
=91X²-130X-147X+210
=91X²-277X+210

追问

还有那张图片，如果姐姐会的话请指点。