(5a+b-3)+(-3a-2b+7)= (7x+y-1)-(-8x-y-1)= 3a(2a+4b)= 2x-6(2-x)= 6x+15= 6x²y-9xy²-12xy²= 6x+15x²-8-20x= z góry dziękuje .

opuszcasz nawiasy :) redukujesz tez wyrazy podobne (5a+b-3)+(-3a-2b+7)= 5a+b-3-3a-2b+7=2a-b+5

(5a+b-3)+(-3a-2b+7)= 5a+b-3-3a-2b+7 = 2a-b+4 (7x+y-1)-(-8x-y-1)= 7x+y-1+8x+y+1 = 15x+2y 3a(2a+4b)= 6a²+12ab 2x-6(2-x)= 2x-12+6x = 8x-12 6x+15= 6x+15 6x²y-9xy²-12xy²= 6x²y-21xy² 6x+15x²-8-20x= -14x+15x²-8

= 5a+b-3-3a-3b+7=2a-2b+4 =7x+y-1+8x+y+1=15x+2y =6a²+12ab =2x-12+x =6x+15 =6x²y-21xy² =-14x+15x²-8 ;))