1.(2x²-3x-7)乘5x-7(1-5x)
=10x³-15x²-35x-7+35x
=10x³-15x²-7
2.(3x³-4x²+2x-5)乘(2x²-5x-7)
=6x^5-15x^4-21x³-8x^4+20x³+28x²+4x³-10x²-14x-10x²+25x+35
=6x^5-23x^4+3x³+8x²+11x+35
1.(2x²-3x-7)乘5x-7(1-5x)
=10x³-15x²-35x-7+35x
=10x³-15x²-7
2.(3x³-4x²+2x-5)乘(2x²-5x-7)
=6x^5-15x^4-21x³-8x^4+20x³+28x²+4x³-10x²-14x-10x²+25x+35
=6x^5-23x^4+3x³+8x²+11x+35