x+3+15+x+4-15求解
@詹路2571：(x+1)(x+3)(x+5)(x+7)+15 求具体过程
宣唯19396391252…… (x+1)(x+3)(x+5)(x+7)+15 =(x+1)(x+7)(x+3)(x+5)+15 =(x²+8x+7)(x²+8x+15)+15 =(x²+8x)²+22(x²+8x)+105+15 =(x²+8x)²+22(x²+8x)+120 =(x²+8x+12)(x²+8x+10) =(x+2)(x+6)(x²+8x+10) 或者=(x+2)(x+6)(x+4-根号6)(x+4+根号6)
@詹路2571：已知3<=x<=15,要求sqrt(9+(x - 3)*(x - 3))+sqrt(4+(15 - x)*(15 - x))最小,求X
宣唯19396391252…… 可以把:S=sqrt(9+(x-3)*(x-3))+sqrt(4+(15-x)*(15-x))看成是两点A(0,3),B(1,15)与点C(3,x)之间距离和即 S=AC+BC AC=sqrt[(0-3)^2+(x-3)^2] BC=sqrt[(1-3)^2+(15-x)^2] ^是指数函数 这样求S的最小值变成求:在直线x=3上求一点(3<=y<15),使AC...
@詹路2571：F(X)=(x+1)(x+3)(2+x)(x+4)+15求值域... -
宣唯19396391252…… 请采纳,谢谢~如有不懂请追问f(x)=(x+1)(x+2)(x+3)(x+4)+15=(x+1)(x+4)(x+2)(x+3)+15=(x^2+5x+4)(x^2+5x+6)+15=(x^2+5x)^2+10(x^2+5x)+39=(x^2+5x+5)^2+14>=14当且仅当x^+5x+5=0,即x1=(-5+√5)/2或x2=(-5-√5)/2时等号成立所以值域是[14,正无穷)
@詹路2571：求y=(x - 1)(x - 2)(x - 3)(x - 4)+15的值域 -
宣唯19396391252…… y=[(x-1)(x-4)][(x-3)(x-2)]+15 =(x^2-5x+4)(x^2-5x+6)+15 =[(x^2-5x+5)-1][(x^2-5x+5)+1]+15 =[x^2-5x+5]^2-1+15 x^2-5x+5=(x-5/2)^2-5/4>=-5/4; 所以[x^2-5x+5]^2>=0; y>=14;
@詹路2571：求解方程8(4x+16)+15=2760. -
宣唯19396391252…… 2(4x-3)+(15-2x)=12+248x-6+15-2x=368x-2x=36+6-156x=27x=27/6=9/2x=4.5朋友,请【采纳答案】,您的采纳是我答题的动力,谢谢.
@詹路2571：x+3/4x=14/15 -
宣唯19396391252…… 解: x+3/4x=14/15 (4+3)/x=14/15 7/x=14/15 7=14x/15 14x=7*15 14x=105 x=7.5 望采纳,谢谢
@詹路2571：(37.5x+15)\(x+15)=4\9求大神解答 -
宣唯19396391252…… 9(0.375+15)=4(x+15)解它就可以了
@詹路2571：x4 - x3+6x2 - x+15因式分解 -
宣唯19396391252…… x4-x3+6x2-x+15=(x^2+x+3)(x^2-2x+5)
@詹路2571：解方程:﹙x - 5﹚﹙x+3﹚+﹙x - 2﹚﹙x+4﹚=49 -
宣唯19396391252…… ﹙x-5﹚﹙x+3﹚+﹙x-2﹚﹙x+4﹚=49 (x^2-2x-15)+(x^2+2x-8)=49 2x^2-23=49 x^2=36 x1=6, x2=-6 ﹙x²-x+1﹚﹙x²-x+2﹚=12 ﹙x²-x+1﹚﹙x²-x+1+1﹚=12 ﹙x²-x+1﹚^2+﹙x²-x+1﹚-12=0 ﹙x²-x+1+4﹚﹙x²-x+1-3﹚=0 ﹙x²-x+5﹚﹙x²-x-2﹚=0 则 (x-2)(x+1)=0 x1=2, x2=-1x²+2﹙√2-1﹚x+3-2√2=0 x²+2﹙√2-1﹚x+(√2-1)^2=0 (x+√2-1)^2=0 x=1-√2
@詹路2571：2x+45+15=(x - 15)*4,求x等于? -
宣唯19396391252…… 2x+45+15=(x-15)*4解:2x+60=(x-15)*4 2x+60=4x-60 4x-2x=60+60 2x=120 x=60很高兴为你解答,如果答案对你有帮助,请点击【选为满意答案】,O(∩_∩)O谢谢!
宣唯19396391252…… (x+1)(x+3)(x+5)(x+7)+15 =(x+1)(x+7)(x+3)(x+5)+15 =(x²+8x+7)(x²+8x+15)+15 =(x²+8x)²+22(x²+8x)+105+15 =(x²+8x)²+22(x²+8x)+120 =(x²+8x+12)(x²+8x+10) =(x+2)(x+6)(x²+8x+10) 或者=(x+2)(x+6)(x+4-根号6)(x+4+根号6)
@詹路2571：已知3<=x<=15,要求sqrt(9+(x - 3)*(x - 3))+sqrt(4+(15 - x)*(15 - x))最小,求X
宣唯19396391252…… 可以把:S=sqrt(9+(x-3)*(x-3))+sqrt(4+(15-x)*(15-x))看成是两点A(0,3),B(1,15)与点C(3,x)之间距离和即 S=AC+BC AC=sqrt[(0-3)^2+(x-3)^2] BC=sqrt[(1-3)^2+(15-x)^2] ^是指数函数 这样求S的最小值变成求:在直线x=3上求一点(3<=y<15),使AC...
@詹路2571：F(X)=(x+1)(x+3)(2+x)(x+4)+15求值域... -
宣唯19396391252…… 请采纳,谢谢~如有不懂请追问f(x)=(x+1)(x+2)(x+3)(x+4)+15=(x+1)(x+4)(x+2)(x+3)+15=(x^2+5x+4)(x^2+5x+6)+15=(x^2+5x)^2+10(x^2+5x)+39=(x^2+5x+5)^2+14>=14当且仅当x^+5x+5=0,即x1=(-5+√5)/2或x2=(-5-√5)/2时等号成立所以值域是[14,正无穷)
@詹路2571：求y=(x - 1)(x - 2)(x - 3)(x - 4)+15的值域 -
宣唯19396391252…… y=[(x-1)(x-4)][(x-3)(x-2)]+15 =(x^2-5x+4)(x^2-5x+6)+15 =[(x^2-5x+5)-1][(x^2-5x+5)+1]+15 =[x^2-5x+5]^2-1+15 x^2-5x+5=(x-5/2)^2-5/4>=-5/4; 所以[x^2-5x+5]^2>=0; y>=14;
@詹路2571：求解方程8(4x+16)+15=2760. -
宣唯19396391252…… 2(4x-3)+(15-2x)=12+248x-6+15-2x=368x-2x=36+6-156x=27x=27/6=9/2x=4.5朋友,请【采纳答案】,您的采纳是我答题的动力,谢谢.
@詹路2571：x+3/4x=14/15 -
宣唯19396391252…… 解: x+3/4x=14/15 (4+3)/x=14/15 7/x=14/15 7=14x/15 14x=7*15 14x=105 x=7.5 望采纳,谢谢
@詹路2571：(37.5x+15)\(x+15)=4\9求大神解答 -
宣唯19396391252…… 9(0.375+15)=4(x+15)解它就可以了
@詹路2571：x4 - x3+6x2 - x+15因式分解 -
宣唯19396391252…… x4-x3+6x2-x+15=(x^2+x+3)(x^2-2x+5)
@詹路2571：解方程:﹙x - 5﹚﹙x+3﹚+﹙x - 2﹚﹙x+4﹚=49 -
宣唯19396391252…… ﹙x-5﹚﹙x+3﹚+﹙x-2﹚﹙x+4﹚=49 (x^2-2x-15)+(x^2+2x-8)=49 2x^2-23=49 x^2=36 x1=6, x2=-6 ﹙x²-x+1﹚﹙x²-x+2﹚=12 ﹙x²-x+1﹚﹙x²-x+1+1﹚=12 ﹙x²-x+1﹚^2+﹙x²-x+1﹚-12=0 ﹙x²-x+1+4﹚﹙x²-x+1-3﹚=0 ﹙x²-x+5﹚﹙x²-x-2﹚=0 则 (x-2)(x+1)=0 x1=2, x2=-1x²+2﹙√2-1﹚x+3-2√2=0 x²+2﹙√2-1﹚x+(√2-1)^2=0 (x+√2-1)^2=0 x=1-√2
@詹路2571：2x+45+15=(x - 15)*4,求x等于? -
宣唯19396391252…… 2x+45+15=(x-15)*4解:2x+60=(x-15)*4 2x+60=4x-60 4x-2x=60+60 2x=120 x=60很高兴为你解答,如果答案对你有帮助,请点击【选为满意答案】,O(∩_∩)O谢谢!
