Question

4. Va roggg! Dau coroana !!

Answer 1

${3}^{1974} - {3}^{1973} - {3}^{1972} - 5 \times {9}^{986}$

$= {3}^{1974} - {3}^{1973} - {3}^{1972} - 5 \times { ({3}^{2} )}^{986}$

$= {3}^{1974} - {3}^{1973} - {3}^{1972} - 5 \times {3}^{2 \times 986}$

$= {3}^{1974} - {3}^{1973} - {3}^{1972} - 5 \times {3}^{1972}$

$= {3}^{1972} ( {3}^{2} - 3 - 1 - 5)$

$= {3}^{1972} (9 - 3 - 1 - 5)$

$= {3}^{1972} (6 - 1 - 5)$

$= {3}^{1972} (5 - 5)$

$= {3}^{1972} \times 0$

$= 0$