Question

Calculați b) (3×7⁷-20×7⁶-6×7⁵):49⁷=​

Answer 1

Răspuns:

$(3 \times 7 ^ { 7 } -20 \times 7 ^ { 6 } -6 \times 7 ^ { 5 } ) \div 49 ^ { 7 }$

$\frac{3\times 823543-20\times 7^{6}-6\times 7^{5}}{49^{7}}$

$\frac{2470629-20\times 7^{6}-6\times 7^{5}}{49^{7}}$

$\frac{2470629-20\times 117649-6\times 7^{5}}{49^{7}}$

$\frac{2470629-2352980-6\times 7^{5}}{49^{7}}$

$\frac{117649-6\times 7^{5}}{49^{7}}$

$\frac{117649-6\times 16807}{49^{7}}$

$\frac{117649-100842}{49^{7}}$

$\frac{16807}{49^{7}}$

$\frac{16807}{678223072849}$

$\frac{1}{40353607}$

$\frac{1}{40353607}\approx 0.000000025$

Descompunere în factori⬇️

$\frac{1}{7 ^ {9}} \approx 2.5E-08$

fallow? 5☆ ➡️❤️⬅️

Answer 2

Explicație pas cu pas:

$(3 \times {7}^{7} - 20 \times {7}^{6} - 6 \times {7}^{5} ) : {49}^{7} =$

$= {7}^{5} \times (3 \times {7}^{2} - 20 \times 7 - 6 ) : {( {7}^{2} )}^{7}$

$= {7}^{5} \times (3 \times 49 - 140 - 6 ) : {7}^{14}$

$= {7}^{5} \times (147 - 146) : {7}^{14}$

$= {7}^{5} \times 1 : {7}^{14} = {7}^{5} : {7}^{14}$

$= {7}^{5 - 14} = {7}^{ - 9} = \frac{1}{ {7}^{9} }$