Answer: [tex]-10\sqrt{2}[/tex]
Step-by-step explanation:
[tex]7\sqrt{32} - 6\sqrt{72}[/tex]
= [tex]7\sqrt{(2*2)*(2*2)*2} - 6\sqrt{(2*2)*2*(3*3)}[/tex]
= [tex]7*2*2\sqrt{2} - 6*2*3\sqrt{2}[/tex]
= [tex]28\sqrt{2} - 36\sqrt{2}[/tex]
Now that they have the same radical, we can subtract their coefficents
= [tex](28 - 36)\sqrt{2}[/tex]
= [tex]-8\sqrt{2}[/tex]