\(\frac{a-b}{a+b}=\frac{12}{13}\Leftrightarrow\frac{\frac{a}{b}-1}{\frac{a}{b}+1}=\frac{12}{13}\Leftrightarrow13\left(\frac{a}{b}-1\right)=12\left(\frac{a}{b}+1\right)\Leftrightarrow13.\frac{a}{b}-12.\frac{a}{b}=12+13\Rightarrow\frac{a}{b}=25\)
a, Cho \(\frac{a}{b+c}=\frac{b}{a+c}=\frac{c}{a+b}\) tim gia tri cua moi ti so do.
b, Cho \(\frac{a}{b}=\frac{b}{c}=\frac{c}{a}\).CMR: a=b=c
cho day ti so bang nhau :
\(\frac{2a+b+c+d}{a}=\frac{a+2b+c+d}{b}=\frac{a+b+2c+d}{c}=\frac{a+b+c+2d}{d}\)
tim gia tri bieu thuc:m=\(\frac{a+b}{c+d}+\frac{b+c}{d+a}+\frac{c+d}{a+b}+\frac{d+a}{b+c}\)
cho day ti so bang nhau
\(\frac{2a+b+c+d}{a}=\frac{a+2b+c+d}{b}=\frac{a+b+2c+d}{c}=\frac{a+b+c+2d}{d}\)
tinh gia tri bieu thuc m=\(\frac{a+b}{c+d}=\frac{b+c}{d+a}=\frac{c+d}{a+b}=\frac{d+a}{b+c}\)
1,\(\frac{\frac{3}{3}-\frac{3}{5}+\frac{3}{11}+\frac{3}{13}}{\frac{7}{3}-\frac{7}{5}+\frac{5}{11}+\frac{5}{13}}\)
2,a,tim x biet:
a,\(\left(3x-2\right)^{10}=\left(3x-2\right)^6\) b\(\left(2x^2-13\right)^4=\left(-5\right)^4\)
3,tim so nguyen n de phan so sau co gia tri la 1 so nguyen va tinh gia tri do
a,A=\(\frac{3n+9}{n-4}\) b,B=\(\frac{6n+5}{2n-1}\)
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a, cho day ti so bang nhau : \(\frac{2a+b+c+d}{a}=\frac{a+2b+c+d}{b}=\frac{a+b+2c+d}{c}=\frac{a+b+c+2d}{d}\)
tinh gia tri bieu thuc M: \(\frac{a+b}{c+d}+\frac{b+c}{d+a}+\frac{c+d}{a+b}+\frac{d+a}{b+c}\)
b,cho x= \(1+\frac{1}{2013}+\frac{1}{2013^2}+\frac{1}{2013^3}+....+\frac{1}{2013^{2013}}\)
tinh gia tri bieu thuc: S= (2012x+\(\frac{1}{2013^{2013}}\)) : 2013^2014
cho\(\frac{a}{2}=\frac{b}{5}=\frac{c}{7}\)tim gia tri cua bieu thuc \(A=\frac{a-b+c}{a+2b-c}\)
Cho cac so a,b,c va thoa man\(\frac{a}{a+b}+\frac{b}{b+c}+\frac{c}{c+a}=2\)Tinh gia tri bieu thuc \(P=\frac{b}{a+b}+\frac{c}{b+c}+\frac{a}{c+a}\)
cho cac so a,b,c va thoa man \(\frac{ab}{a+b}=\frac{1}{3},\frac{bc}{b+c}=\frac{1}{4},\frac{ca}{c+a}=\frac{1}{5}\)Tinh gia tri bieu thuc P=\(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}\)
cau 1: Cho A= \(\frac{100^{2014}+2}{3}-\frac{100^{2015}+17}{9}.\)tong cac cua so cua B=-9A
Cau 2: So sanh A=\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+........+\frac{1}{100.101}\)voi 1 ta doc A....1
Cau 3 : Cho bon so a,b,c,d sao cho a+b+c+d khac 0 . Biet \(\frac{b+c+d}{a}=\frac{c+d+a}{b}=\frac{d+a+b}{c}=\frac{a+b+c}{d}=k\). Vay k=
Cau 4 : so cac so nguyen am x thoa man \(x^{2015}=\left(-2\right)^{2014}\)
Cau 5; tim x,y,z biet \(\frac{x}{y}=\frac{10}{9},\frac{y}{z}=\frac{3}{4}\)va x-y+z=78
Cau 6: tap hop cac so co ba chu so chia het cho 18 va tong cac chu so ti le voi 1;2;3 la
Cau 7: gia tri cua tong S=1.2+2.3+.....+49.50 la S=
