试用配方法证明5x²-6x 11的值恒大于零
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6x-3x^2-7原式=6x-3x^2+3-3-7=-3(x^2-2x+1)+3-7=-3(x-1)^2-4∵(x-1)^2≥0∴-3(x-1)^2≤0∴-3(x-1)^2-4<0∴6x-3x^2-7
5x^2-6x+10+4/5=5(x^2-6x/5)+10+4/5=5(x^2-6x/5+9/25)-9/5+10+4/5=5(x-3/5)^2+9因为5(x-3/5)^2>=0,所以5(x-3/5)
6x-3x²-7=-3x²+6x-7=-3(x²-2x)-7=-3[(x²-2x+1)-1]-7=-3(x-1)²+3-7=-3(x-1)²
x^4-3x^2+1=(x^2)^2-2x^2+1-x^2=(x^2-1)^2-x^2=(x^2-x-1)(x^2+x-1)
当x=3/4时,代数式-2x²+3x-3的最大值为-15/8.3x²-6x+5=3(x²-2x+1-1)+5=3[(x-1)²-1]+5=3(x-1)²
再问:口莫哒是我打错了应该是-12x再答:好滴再答:再问:简直太棒再答:没事再问:再追问一下为什么把-12提出来后剩下的是16/1呢再答:有个配方公式再答:你们老师应该讲过了再问:错了错了是把-12提
原式=5(X²-6X/5+9/25-9/25)+11=5(X²-6X/5+9/25)-9/5+11=5(X-3/5)²+46/5≥46/5>0所以恒大于0
5X²-6x+11=5(X²-6x/5)+11=5[(X²-6x/5+9/25)-9/25]+11=5(x-3/5)²-9/5+11=5(x-3/5)²
x2+4x-5=x2+4x+4-9=(x+2)2-9=(x+2+3)(x+2-3)=(x+5)(x-1)
soeasy首先,把系数化为一,原式=5(x^2-6x/5+1.76)然后,加减一次项系数一半的平方:5(x^2-6x/5+9/25-9/25+1.76)之后把前三项写成完全平方式:5[(x-3/5)
5x²-6x+11=5(x²-6x/5)+11=5(x-3/5)²+11-9/5=5(x-3/5)²+46/5;∵(x-3/5)²≥0;∴5x
再答:采纳可好再答:采纳啊
(-6)x(-0.25)x11/14=3/2x11/14=33/28
5x^2-6x+11=5(x-3/5)^2-9/5+11=5(x-3/5)^2+46/5因为5(x-3/5)^2≥0所以原式=5(x-3/5)^2+46/5≥46/5即最小值为五分之四十六祝学习进步再
∵5x²-6x+11=5(x²-2*3/5x)+11=5(x-3/5)²-9/5+11=5(x-3/5)²+46/55(x-3/5)²≥0∴当x=3/
-2x²-4x-3=-2(x²+2x+1-1)-3=-2(x+1)²-1当x=-1时,有最大值-1,此时小于0故原式成立
2x²-6x+5=2(x²-3x+9/4)-9/2+5=2(x-3/2)²+1/2因为2(x-3/2)²≥0所以2(x-3/2)²+1/2>0也就是2
6x^2-24x+5=6(x^2-4x)+5=6(x^2-4x+4-4)+5=6[(x-2)^2-4]+5=6(x-2)^2-24+5=6(x-2)^2-19,当x=2时,值为-19
题目有问题,应该是-6x平方+24x-25的值小于零证明:-6x²+24x-25=-6(x²-4x+4)+24-25=-6(x-2)²-1因为:(x-2)²≥0