(x+7)²-(x-4)(x+4)= x²+14x+49-x²+16= 14x+65
1) <span>-2x/7 - 3=1</span>
(10+x)(100-10x+x²)-x³-500x<0
1000-100x+10x²+100x-10x²+x³-x³-500x<0
1000-500x<0
-500x<-1000
x>2