Question

A eguacao x² - 13x +40=0 admite duas raizes. A maior delas e:
a) ( )5. b) ( )6. c) ( )7. d) ( )8

Answer 1

$- ( - 13) \sqrt{ - ( { - 13)}^{2} - 4 \times 1 \times 40 } \div 2 \times 1 \\ 13 \sqrt{169 - 160} \div 2 \\ 13 \sqrt{9} \div 2 \\ \\ 13 + 3 \div 2 = 8 \\ \\ 13 - 3 \div 2 = 5$
letra D