Question

задания! сделай по действиям ​

Answer 1

Решить уравнение:

1)

$\frac{x}{12}-\frac{x}{8}=\frac{7}{6}\\\\\frac{x}{12}\cdot \:24-\frac{x}{8}\cdot \:24=\frac{7}{6}\cdot \:24\\\\2x-3x=28\\-x=28\\x=-28$

2)

$\frac{13x}{21}+\frac{9x}{14}=-1\\\\\frac{13x}{21}\cdot \:42+\frac{9x}{14}\cdot \:42=-1\cdot \:42\\\\26x+27x=-42\\\\53x=-42\\x=-\frac{42}{53}$

3)

$-\frac{3x}{10}-\frac{7}{15}=\frac{x}{6}\\\\-\frac{3x}{10}\cdot \:30-\frac{7}{15}\cdot \:30=\frac{x}{6}\cdot \:30\\\\-9x-14=5x\\-9x-5x=14\\-14x=14\\x=-1$

Найти корень уравнения:

1)

$\frac{x}{3}+\frac{x}{12}=\frac{15}{4}\\\\\frac{x}{3}\cdot \:12+\frac{x}{12}\cdot \:12=\frac{15}{4}\cdot \:12 \\\\4x+x=45\\5x=45\\x=9$

2)

$\frac{7x}{9}-\frac{3x}{4}=\frac{5}{12}\\\\\frac{7x}{9}\cdot \:36-\frac{3x}{4}\cdot \:36=\frac{5}{12}\cdot \:36\\\\28x-27x=15\\\\x=15$

3)

$1-\frac{8x}{15}=\frac{4x}{9}\\\\1\cdot \:45-\frac{8x}{15}\cdot \:45=\frac{4x}{9}\cdot \:45\\\\45-24x=20x\\20x+24x=45\\44x=45\\x=\frac{45}{44}$