(1), -x^2+6x-10=-(x^2-6x+9)-1=-(x-3)^2-1
因为(x-3)^2≥0,所以-(x-3)^2≤0,-(x-3)^2-1<0,
-x^2+6x-10<0恒成立
(2),4x^2-12x+10=4[x^2-3x+(3/2)^2]-4*(3/2)^2+10=4(x-3/2)^2+7>0恒成立
1:-x²+6x-10
=-(x²-6x+10)
=-(x-3)²-1
因为(x-3)²>=0
所以-(x-3)²-1<0
-x²+6x-10的值恒小于零
2:4x²-12x+10
=(2x-3)²-9+10
=(2x-3)²+1
因为(2x-3)²>=0
所以(2x-3)²+1>0
原式恒大于零
:(1)-(x平方)+6x-10的值恒小于零;
-x²+6x-10
=-(x²-6x+9)-1
=-(x-3)²-1<0
(2)4(x平方)-12x+10的值恒大于零
4x²-12x+10
=4(x²-3x+9/16)+31/4
=4(x-3/2)²+31/4
>0
(1)-(x平方)+6x-10的值恒小于零;
=-[(x-3)^2+1]
不论x取什么值,(x-3)^2≥0
[(x-3)^2+1]≥1
-[(x-3)^2+1]≤0.
1.-x方+6x-10=-x方+6x-9-1=-(x方-6x+9)-1=-(x-3)方-1<=-1<0
2.4(x平方)-12x+10=4(x平方)-12x+9+1=(4(x平方)-12x+9)+1=(2x-3)的平方+1》1>0
1.原式=-X^2+6X-9-1=-(X-3)^2-1<=-12.原式=4X^2-12X+9+1=4(X-3/2)^2+1