Question

1 )x^2-(9-x )^2 больше -2x
2)x^2 меньше (25-х)^2+25х

Answer 1

1)
x^2-(9-x )^2 > -2x
x^2-81+18x-x^2+2x>0
20x>81
x>81/20
x>4.05
2)
x^2 < (25-х)^2+25x
x^2<625-50x+x^2+25x
25x<625
x<25