3a+2b+5c

穆邰琛5170已知3a=2b+5,不成立的是A.3a - 5=2b B.3a+1=2b+6 C.3ac=2bc+5 D.a=2/3b+5/3 -
蔚荆苗17374561099 ______ C~~要想两边同时乘c,则两边都应当成整体乘上c.C答案应为3aXc=(2b+5)Xc 即3ac=2bc+5c

穆邰琛5170解2/a+2b+c/=/3a+b+c/ -
蔚荆苗17374561099 ______ 解:a/2=b/3a/2=c/43a=2b2a=c3a-2b+5c/a+b+c=3a-2b+5c/a+c=2b-2b+5*2a/a+b+2a=10+b+2a=10+3a/2+2a=10+3.5a

穆邰琛5170c#怎么计算3a+2b+0.5c==100和a+b+c==100中a b c的值 求代码 -
蔚荆苗17374561099 ______ static void Main(string[] args) {Console.WriteLine(＂计算3a+2b+0.5c==100和a+b+c==100中a b c的值＂);int s = 1; for (int a = 0; a <=100; a++) { for (int b = 0; b< 100; b++) { for (int c= 0; c< 100;c++) { if (3 * a + 2 * b + 0.5 * c == 100 && a + b + c ...

穆邰琛5170已知二分之A=三分之B - 四分之C,求A+B+C分之3A - 2B+5C的值简便方法 -
蔚荆苗17374561099 ______[答案] 由A/2=B/3,得B=3A/2(1) 由A/2=C/4,得C=2A(2) 所以(3A-2B+5C)/(A+B+C) =(3A-3A+10A)/(A+3A/2+2A) =10A/(9A/2) =20/9.

穆邰琛5170已知a+b - c=0,2a - b+2c=0(c≠0),求3a - 2b+5c/5a - 3b+2c的值 -
蔚荆苗17374561099 ______ a+b-c=0, 所以 a+b=c --- (1) 2a-b+2c=0 所以 2a-b=-2c --- (2) (2)+(1) 得3a=-c a=-1/3c 则: b=4/3c (3a-2b+5c)/(5a-3b+2c)= (-c-8/3c+5c)/(-5/3c-4c+2c)=-4/11 (c≠0)

穆邰琛5170求方程的所有非负数解:3a+4b+5c=78 -
蔚荆苗17374561099 ______ 5x+3y=22 y=(22-5x)/3=7-2x+(1+x)/3 则(1+x)/3是整数 令a=(1+x)/3 x=3a-1 y=(22-15a+5)/3=9-5a x>=0,y>=0 所以3a-1>=0,a>=1/39-5a>=0,a1/3所以a=1 所以x=2,y=4

穆邰琛5170若2分之a=3分之b=4分之c,则a+b+c分之3a - 2b+5c=? -
蔚荆苗17374561099 ______[答案] 令:a/2 = b/3 = c/4 = m 则:a=2m,b=3m,c=4m (3a-2b+5c)/(a+b+c) = (6m-6m+20m)/(3m+2m+4m) = 20/9

穆邰琛5170已知3a加4b加5c等于1.求a方加b方加c方.的最小值. -
蔚荆苗17374561099 ______[答案] 依Cauchy不等式得a²+b²+c²=(3a)²/9+(4b)²/16+(5c)²/25≥(3a+4b+5c)²/(9+16+25)=1/50.∴a:3=b:4=c:5且3a+4b+5c=1,即a=3/50,b=2/25,c=1/10时,所求最小值为: 1/50....

穆邰琛5170已知二分之A=三分之B - 四分之C,求A+B+C分之3A - 2B+5C的值是多少 -
蔚荆苗17374561099 ______[答案] 已知二分之A=三分之B等于四分之C, A=C/2 B=3C/4 A+B+C分之3A-2B+5C的值 =(3A-2B+5C)/(A+B+C) =(3*C/2-2*3C/4+5C)/(C/2+3C/4+C) =5C/(9C/4) =20/9

穆邰琛5170已知A+B - C=0 2A - B+2C=0 C不等于0 求分式的解求3A - 2B+5C/5A - 3B+2C -
蔚荆苗17374561099 ______[答案] A+B-C=0 2A-B+2C=0 + 3A+C=0 C=-3A B=-4A 3A-2B+5C/5A-3B+2C =(3A+8A-15A)/(5A+12A-6A) =4/11