Question

Tìm \(x\) biết:

a,\(x:\left(\frac{-1}{3}\right)^3=-\frac{1}{3}\)                     b,\(x:0,16=9:x\)                        c,|\(x+\frac{4}{5}\) |-\(\frac{1}{7}=0\)

Answer 1

c)/x+\(\frac{4}{5}\)/=\(\frac{1}{7}\)

=>x+\(\frac{4}{5}\)=\(\frac{1}{7}\) hoặc x+\(\frac{4}{5}\)=\(\frac{-1}{7}\)

     x=\(\frac{1}{7}\)-\(\frac{4}{5}\)           x=\(\frac{-1}{7}\)-\(\frac{4}{5}\)

     x=\(\frac{-23}{35}\)            x=\(\frac{-33}{35}\)

Answer 2

a)x:\(\left(\frac{-1}{3}\right)^3\)=\(\left(\frac{-1}{3}\right)^1\)

x=\(\left(\frac{-1}{3}\right)^1\)*\(\left(\frac{1}{-3}\right)^3\)

x=\(\left(\frac{-1}{3}\right)^4\)

x=\(\frac{1}{81}\)

b)x:0,16=9:x

=>x:0,16:x=9:x:x

=>0,16=9:\(x^2\)

=>9:\(x^2\)=0,16

=>\(x^2\)=9:0,16

=>\(x^2\)=\(\frac{225}{4}\)

=>\(x\)=\(\frac{15}{2}\)