Respuesta :

gustanika
We need to simplify the root by factoring the number in the root
7√28 - 5√63
= [tex]7 \sqrt{4 \times 7} - 5 \sqrt{9 \times 7} [/tex]
= (7 × √4 × √7) - (5 × √9 × √7)
= (7 × 2 × √7) - (5 × 3 × √7)
= 14√7 - 15√7
= -√7
The answer is first option