13x²+5x-2≤0D=25+24=49x1=(-5-7)/6=-2x2=(-5+7)/2=1 + _ +---------------[-2]-----------------[1]------------------x∈[-2;1]23x²-15≤03(x²-5)≤03(x-√5)(x+√5)≤0x=√5 x=-√5 + _ +---------------[-√5]-----------------[√5]------------------x∈[-√5;√5]425-100x²>0(5-10x)(5+10x)>0x=0,5 x=-0,5 _ + _---------------(-0,5)-----------------(0,5)------------------x∈(-0,5;0,5)55x²-26x+5≤0D=676-100=576x1=(26-24)/10=0,2x2=(26+24)/10=5 + _ +---------------[0,2]-----------------[5]------------------x∈[0,2;5]