a) \(\dfrac{1}{4}+\dfrac{\dfrac{3}{4}}{3x}=-5\)
\(\dfrac{\dfrac{3}{4}}{3x}=-5-\dfrac{1}{4}\)
\(\dfrac{\dfrac{3}{4}}{3x}=-\dfrac{21}{4}\)
\(3x=\dfrac{\dfrac{3}{4}}{-\dfrac{21}{4}}\)
\(3x=-\dfrac{1}{7}\)
\(x=\dfrac{-\dfrac{1}{7}}{3}\)
\(x=-\dfrac{1}{21}\)
a) 1/4 + 3/4 : 3x = -5
3/4 : 3x = -5 - 1/4
3/4 : 3x = -21/4
3x = 3/4: -21/4
3x = 1/-7
x = 1/-7 : 3
x = 1/-21
b) x - 25%x = 0,5
1.x - 1/4 . x = 1/2
(1 - 1/4) . x = 1/2
3/4 . x = 1/2
x = 1/2 : 3/4
x = 1/2 . 4/3
x = 2/3
b) \(x-25\%x=0,5\)
\(x-\dfrac{25}{100}x=\dfrac{1}{2}\)
\(x-\dfrac{1}{4}x=\dfrac{1}{2}\)
\(x\left(1-\dfrac{1}{4}\right)=\dfrac{1}{2}\)
\(\dfrac{3}{4}x=\dfrac{1}{2}\)
\(x=\dfrac{\dfrac{1}{2}}{\dfrac{3}{4}}\)
\(x=\dfrac{2}{3}\)
\(\dfrac{4}{x}-6=\dfrac{y}{24}=-\dfrac{12}{18}\)
* Tìm x
\(\dfrac{4}{x}-6=-\dfrac{12}{18}\)
\(\dfrac{4}{x}=-\dfrac{12}{18}+6\)
\(\dfrac{4}{x}=\dfrac{16}{3}\)
\(x=\dfrac{4}{\dfrac{16}{3}}=\dfrac{3}{4}\)
* Tìm y
\(\dfrac{y}{24}=-\dfrac{12}{18}\)
\(y=-\dfrac{12}{18}.24\)
\(y=-16\)