Thực hiện phép tính (tính nhanh nếu có thể)
( $\frac{7}{8}$ – $\frac{3}{4}$ ). 1$\frac{1}{3}$ -$\frac{2}{7}$ . $(3,5)^{2}$
Thực hiện phép tính (tính nhanh nếu có thể)
( $\frac{7}{8}$ – $\frac{3}{4}$ ). 1$\frac{1}{3}$ -$\frac{2}{7}$ . $(3,5)^{2}$
Ta có:
$\left(\frac{7}{8}-\frac{3}{4}\right)\cdot 1\frac{1}{3}-\frac{2}{7}\cdot \left(3,\:5\right)^2$
$=\left(\frac{7}{8}-\frac{3}{4}\right)\cdot \:\frac{4}{3}-\frac{2}{7}\cdot \:\frac{49}{4}$
$=\left(\frac{7}{8}-\frac{6}{8}\right)\cdot \frac{4}{3}-\frac{2}{7}\cdot \frac{49}{4}$
$=\frac{1}{8}\cdot \frac{4}{3}-\frac{2}{7}\cdot \frac{49}{4}$
$=\frac{1}{6}-\frac{7}{2}$
$=\frac{1}{6}-\frac{21}{6}$
$=-\frac{20}{6}$
$=-\frac{10}{3}$
`( 7/8 – 3/4 ) . 1 1/3 – 2/7 . ( 3,5 )^2`
`= ( 7/8 – 6/8 ) . 4/3 – 2/7 . ( 7/2 )^2`
`= 1/8 . 4/3 – 2/7 . 49/4`
`= 1/6 – 7/2`
`= 2/12 – 42/12`
`= (-10)/3`