Câu 1:
a) 5.$\frac{2}{15}$ - $\frac{1}{2}$ = $\frac{2}{3}$ - $\frac{1}{2}$ = $\frac{4}{6}$ - $\frac{3}{6}$ = $\frac{1}{6}$
b) $\frac{2}{7}$.$\frac{5}{3}$ + $\frac{2}{7}$.$\frac{-15}{3}$ - $\frac{5}{7}$.$\frac{10}{3}$ = $\frac{2}{7}$.($\frac{5}{3}$ + $\frac{-15}{3}$) - $\frac{5}{7}$.$\frac{10}{3}$ = $\frac{2}{7}$.$\frac{10}{3}$ - $\frac{5}{7}$.$\frac{10}{3}$ = $\frac{10}{3}$.($\frac{5}{7}$+$\frac{2}{7}$) = $\frac{10}{3}$.1 = $\frac{10}{3}$
c) ($\frac{1}{3}$+$\frac{3}{4}$-$\frac{13}{12}$):($\frac{12}{23}$+$\frac{123}{234}$-$\frac{1234}{2345}$) = ($\frac{4}{12}$+$\frac{9}{12}$-$\frac{13}{12}$):($\frac{12}{23}$+$\frac{123}{234}$-$\frac{1234}{2345}$) = 0:($\frac{12}{23}$+$\frac{123}{234}$-$\frac{1234}{2345}$) = 0
Câu 2:
a) x - $\frac{3}{4}$ = 1$\frac{1}{2}$
=> x - $\frac{3}{4}$ = $\frac{3}{2}$
=> x = $\frac{3}{2}$ + $\frac{3}{4}$
=> x = $\frac{6}{4}$ + $\frac{3}{4}$
=> x = $\frac{3}{2}$
b) |$\frac{3}{4}$x-1| - $\frac{1}{2}$ = 4
=>|$\frac{3}{4}$x-1| = 4 + $\frac{1}{2}$
=>|$\frac{3}{4}$x-1| = $\frac{9}{2}$
=> $\frac{3}{4}$x-1 = $\frac{9}{2}$ hoặc $\frac{3}{4}$x-1 = $\frac{-9}{2}$
=> $\frac{3}{4}$x = $\frac{9}{2}$+1 hoặc $\frac{3}{4}$x = $\frac{-9}{2}$+1
=> $\frac{3}{4}$x = $\frac{11}{2}$ hoặc $\frac{3}{4}$x = $\frac{-7}{2}$
=> x = $\frac{22}{3}$ hoặc x = $\frac{-14}{3}$
c) (2x - $\frac{1}{2}$)($\frac{3}{4}$ + 3x) = 0
=> 2x - $\frac{1}{2}$ = 0 hoặc $\frac{3}{4}$ + 3x = 0
=> 2x = $\frac{1}{2}$ hoặc 3x = -$\frac{3}{4}$
=> x = $\frac{1}{2}$ hoặc x = $\frac{-1}{4}$
