Question

[Lê Ngọc Nhã Phương]

  ai giỏi mới trả lời đc nha

Answer 1

[lê đức anh]

e) \(17-\sqrt{x+5}=3\)

\(\Rightarrow\sqrt{x+5}=17-3=14\)

\(\Rightarrow x+5=14^2=196\)

\(\Rightarrow x=196-5=191\)

f) \(3^x+3^{x+4}-5.3^{x+1}=603\)

\(3^x+3^x.3^4-5.3.3^x=603\)

\(\Rightarrow3^x\left(1+3^4-5.3\right)=603\)

\(\Rightarrow3^x\left(1+81-15\right)=603\)

\(\Rightarrow3^x.67=603\Rightarrow3^x=9\Rightarrow x=2\)

g) \(\frac{x-3}{97}+\frac{x-5}{95}-\frac{x-10}{90}=-1\)

\(\Rightarrow\left(\frac{x-3}{97}-1\right)+\left(\frac{x-5}{95}-1\right)-\left(\frac{x-10}{90}-1\right)=-2\)

\(\Rightarrow\frac{x-100}{97}+\frac{x-100}{95}-\frac{x-100}{90}=-2\)

\(\Rightarrow\left(x-100\right)\left(\frac{1}{97}+\frac{1}{95}-\frac{1}{90}\right)=-2\)

\(\Rightarrow\left(x-100\right).\frac{1613}{165870}=-2\)

\(\Rightarrow x-100=-2:\frac{1613}{165870}=-2.\frac{165870}{1613}=-\frac{331740}{1613}\)

\(\Rightarrow x=-\frac{331740}{1613}+100=-\frac{170440}{1613}\approx-105,667\)