Can anyone help me with this?

Answer:
[tex]\sqrt{7}[/tex]
Step-by-step explanation:
Given
4[tex]\sqrt{7}[/tex] - 10[tex]\sqrt{7}[/tex] + 7[tex]\sqrt{7}[/tex] ( add the coefficients of the terms )
= (4 - 10 + 7) [tex]\sqrt{7}[/tex]
= 1[tex]\sqrt{7}[/tex]
= [tex]\sqrt{7}[/tex]