Answer:
7[tex]\sqrt{7}[/tex]
Step-by-step explanation:
Take 9 out of [tex]\sqrt{63}[/tex]
You get 3[tex]\sqrt{7}[/tex]
Take 4 out of [tex]\sqrt{28}[/tex]
You get 2[tex]\sqrt{7}[/tex]
So, 3(3[tex]\sqrt{7}[/tex]) - 2[tex]\sqrt{7}[/tex]
= 9 [tex]\sqrt{7}[/tex] - 2[tex]\sqrt{7}[/tex]
=7[tex]\sqrt{7}[/tex]
