tim x:\(2^{x+2}-2^x\)=96
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\(2^{x+2}-2^x=96\)
\(2^x.\left(2^2-1\right)=96\)
\(2^x.3=96\)
\(2^x=32\)
\(2^x=2^5\)
\(\Rightarrow x=5\)
\(2^{x+2}-2^x=96\)
\(2^x\left(2^2-1\right)=96\)
\(2^x\left(4-1\right)=96\)
\(2^x\cdot3=96\)
\(2^x=96:3\)
\(2^x=32\)
\(2^x=2^5\)
\(x=5\)
2x + 2x + 1 = 96
=> 2x(1+2)=96
=>2x.3=96
=> 2x=96:3=32
=> 2x=32=25
=> x=5
Vây x=5
2x + 2x+1 = 96
2x + 2x . 2 =96
2x . (1 + 2)= 96
2x. 3 = 96
2x = 96:3=32
mà 32 = 25 => x = 5
Vậy x = 5
Ta có:
\(\frac{x+1}{98}+1+\frac{x+2}{97}+1=\frac{x+3}{96}+1+\frac{x+4}{95}+1\)
\(\frac{x+1}{98}+\frac{98}{98}+\frac{x+2}{97}+\frac{97}{97}=\frac{x+3}{96}+\frac{96}{96}+\frac{x+4}{95}+\frac{95}{95}\)
\(\frac{x+99}{98}+\frac{x+99}{97}=\frac{x+99}{96}+\frac{x+99}{95}\)
\(\frac{x+99}{98}+\frac{x+99}{97}-\frac{x+99}{96}-\frac{x+99}{95}=0\)
\(\left(x+99\right)\left(\frac{1}{98}+\frac{1}{97}-\frac{1}{96}-\frac{1}{95}\right)=0\)
Vì: \(\frac{1}{98}+\frac{1}{97}-\frac{1}{96}-\frac{1}{95}\ne0\)nên x+99=0
=> x=-99
4x + (1/99+2/98+3/97 + 4/96)=-4
4x=-4 - (1/99+2/98+3/97 + 4/96)
4x=
\(\frac{2}{x}=\frac{3}{y}\Rightarrow x=\frac{2y}{3}\)
Thay vào x . y, ta được:
\(x\cdot y=\frac{2y}{3}\cdot y=\frac{2y^2}{3}=96\)
=> \(2y^2=96\cdot3=288\Rightarrow y^2=\frac{288}{2}=144\)
=> \(y=\sqrt{144}=12\) hoặc \(y=-12\)
- y = 12 => x = 96 : 12 = 8
- y = -12 => x = 96 : (-12) = -8
Vậy x = 8; y = 12 hoặc x = -8 ; y = -12
\(\frac{2}{x}=\frac{3}{y}=>\frac{2}{x}.\frac{3}{y}=\frac{3}{y}.\frac{3}{y}=>\frac{6}{xy}=\frac{9}{y^2}=>\frac{6}{96}=\frac{9}{y^2}=>\frac{1}{16}=\frac{9}{y^2}\)
\(=>y^2=9:\frac{1}{16}=144=12^2=\left(-12\right)^2\)
=>y=12,-12
Với y=12=>x=96:12=8
Với y=-12=>x=96:(-12)=-8
Vậy x=-8,y=-12
x=8,y=12
de ot giai violympic ma cau ko bit lam bai nay a. Bai nay cach lam dai Khi nao ranh to ghi cho
a) \(2^{x+2}-2^2=96\)
<=> \(2^x.2^2-2^x=96\)
<=> \(2^x\left(4-1\right)=96\)
<=> \(3.2^x=96\)
<=> \(2^x=32\)
<=> \(2^x=2^5\)
<=> x = 5
b, \(x-\left(\frac{50x}{100}+\frac{25x}{200}\right)=11\frac{1}{4}\)
\(\Rightarrow x-\left(\frac{1x}{2}+\frac{1x}{8}\right)=\frac{45}{4}\)
\(\Rightarrow x-\left(\frac{4x}{8}+\frac{1x}{8}\right)=\frac{45}{4}\)
\(\Rightarrow x-\frac{5x}{8}=\frac{45}{4}\)
\(\Rightarrow\frac{8x}{8}-\frac{5x}{8}=\frac{45}{4}\)
\(\Rightarrow\frac{3x}{8}=\frac{45}{4}\Rightarrow x=\frac{45}{4}\div\frac{3}{8}=30\)
Vậy x = 30
2x + 2 - 2x - 96
=> 2x . 22 - 2x . 1 = 96
=> 2x (22 - 1) = 96
=> 2x . 3= 96
=> 2x = 96 : 3 =32
=> x = 5
2x + 2 - 2x = 96
=> 2x . 22 - 2x . 1 = 96
=> 2x (22 - 1) = 96
=> 2x . 3= 96
=> 2x = 96 : 3 =32
=> x=5.