Question

o valor de 7 √80 é

a)28 √5
b)14 √5
c)35 √2
d)40 √5​

Answer 1

$\sf 7\sqrt{80}\\\\\\\sf =7\sqrt{2^4\cdot \:5}\\\\\\\sf {Aplicar\:as\:propriedades\:dos\:radicais}:\quad \sqrt{ab}=\sqrt{a}\sqrt{b},\:\quad \:a\ge 0,\:b\ge 0\\\\\\\sf =7\sqrt{2^4}\sqrt{5}\\\\\\\sf =7\cdot \:4\sqrt{5}\\\\\\\to\boxed{\sf =28\sqrt{5}}$