2/7*21/8-1/7*(5/2-4)= eching

$$\frac { 2 } { 7 } \cdot \frac { 21 } { 8 } - \frac { 1 } { 7 } \cdot ( \frac { 5 } { 2 } - 4 ) =$$

Baholash

$$\frac{27}{28}\approx 0,964285714$$

Yechim qadamlari

Suratni maxrajga va maxrajini suratga ko‘paytirish orqali \frac{2}{7} ni \frac{21}{8} ga ko‘paytiring.

$$\frac{2\times 21}{7\times 8}-\frac{1}{7}\left(\frac{5}{2}-4\right)$$

\frac{2\times 21}{7\times 8} kasridagi ko‘paytirishlarni bajaring.

$$\frac{42}{56}-\frac{1}{7}\left(\frac{5}{2}-4\right)$$

\frac{42}{56} ulushini 14 ni chiqarib, bekor qilish hisobiga eng past shartlarga kamaytiring.

$$\frac{3}{4}-\frac{1}{7}\left(\frac{5}{2}-4\right)$$

4 ni \frac{8}{2} kasrga o‘giring.

$$\frac{3}{4}-\frac{1}{7}\left(\frac{5}{2}-\frac{8}{2}\right)$$

\frac{5}{2} va \frac{8}{2} da bir xil maxraji bor, ularning suratini ayirish orqali ayiring.

$$\frac{3}{4}-\frac{1}{7}\times \frac{5-8}{2}$$

-3 olish uchun 5 dan 8 ni ayirish.

$$\frac{3}{4}-\frac{1}{7}\left(-\frac{3}{2}\right)$$

Suratni maxrajga va maxrajini suratga ko‘paytirish orqali \frac{1}{7} ni -\frac{3}{2} ga ko‘paytiring.

$$\frac{3}{4}-\frac{1\left(-3\right)}{7\times 2}$$

\frac{1\left(-3\right)}{7\times 2} kasridagi ko‘paytirishlarni bajaring.

$$\frac{3}{4}-\frac{-3}{14}$$

\frac{-3}{14} kasri manfiy belgini olib tashlash bilan -\frac{3}{14} sifatida qayta yozilishi mumkin.

$$\frac{3}{4}-\left(-\frac{3}{14}\right)$$

-\frac{3}{14} ning teskarisi \frac{3}{14} ga teng.

$$\frac{3}{4}+\frac{3}{14}$$

4 va 14 ning eng kichik umumiy karralisi 28 ga teng. \frac{3}{4} va \frac{3}{14} ni 28 maxraj bilan kasrlarga aylantirib oling.

$$\frac{21}{28}+\frac{6}{28}$$

\frac{21}{28} va \frac{6}{28} da bir xil maxraji bor, ularning suratini qo‘shish orqali qo‘shing.

$$\frac{21+6}{28}$$

27 olish uchun 21 va 6'ni qo'shing.

$$\frac{27}{28}$$

Omil

$$\frac{3 ^ {3}}{2 ^ {2} \cdot 7} = 0,9642857142857143$$