Question

escreva na forma mais simples possivel a expressao (-5 + 2√7)(4 + √7) - 3√7.

Answer 1

$(-5+2 \sqrt{7} ).(4+ \sqrt{7})-3 \sqrt{7}\\(-20-5 \sqrt{7}+4 \sqrt{7}+2.7)-3 \sqrt{7}\\-20+14-4 \sqrt{7}\\-6-4 \sqrt{7}$