Đáp án:
`1)53x+22`
`2)-4x+3`
`3)19x-12`
`4)18x-2`
`5)42x-41`
Giải thích các bước giải:
`1)5(2x+3)(x+2)-2(5x-4)(x-1)`
`=(10x+15)(x+2)-2(5x²-5x-4x+4)`
`=10x²+20x+15x+30-10x²+10x+8x-8`
`=(10x²-10x²)+(20x+15x+10x+8x)+(30-8)`
`=53x+22`
`2)(10x+9)x-(5x-1)(2x+3)`
`=10x²+9x-(10x²+15x-2x-3)`
`=10x²+9x-10x²-15x+2x+3`
`=(10x²-10x²)+(9x-15x+2x)+3`
`=-4x+3`
`3)3(2x-1)-5(x-3)+6(3x-4)`
`=6x-3-5x+15+18x-24`
`=(6x-5x+18x)+(-3+15-24)`
`=19x-12`
`4)(3x-1)(2x+7)-(x+1)(6x-5)`
`=6x²+21x-2x-7-(6x²-5x+6x-5)`
`=6x²+21x-2x-7-6x²+5x-6x+5`
`=(6x²-6x²)+(21x-2x+5x-6x)+(-7+5)`
`=18x-2`
`5)(3x-5)(7-5x)+(5x+2)(3x-2)-2`
`=21x-15x²-35+25x+15x²-10x+6x-4-2`
`=(-15x²+15x²)+(21x+25x-10x+6x)+(-35-4-2)`
`=42x-41`
