1. 13x+7y-10x-4y+5y=13x-10x+7y-4y+5y=(13-10)x+(7-4+5)y=3x+8y
2.a³+2a-a²+3a²-10a³+5=a³-10a³-a²+3a²+2a+5=(1-10)a³+(-1+3)a²+2a+5=-9a³+2a²+2a+5
3.90a+3b-a²-81a-2b+a²=-a²+a²+90a-81a+3b-2b=(-1+1)a²+(90-81)a+(3-2)b=0a²+9a+1b=9a+b
4. 4x²-x-x³+5x-3x³+2x³-4x=-x³-3x³+2x³+4x²-x+5x-4x=(-1-3+2)x³+4x²+(-1+5-4)x=-2x³+4x²+0x=-2x³+4x²
5. 5x²-x²+y²+y-3-y-2y²+5=5x²-x²+y²-2y²+y-y-3+5=(5-1)x²+(1-2)y²+(1-1)y+2=4x²-1y²+0y+2=4x²-y²+2
6. 4u+2u²-2w-3u-9u²+w-u²=2u²-9u²-u²+4u-3u-2w+w=(2-9-1)u²+(4-3)u+(-2+1)w=-8u²+1u-1w=-8u²+u-w
Pozdrawiam ❤️
