Subtract simplify by collecting like radical terms

6square root symbol 75 -7square root symbol 3

I cant figure out how to square 75?

2 answers

sqrt(75)=sqrt(25)sqrt(3)
which simplifies to 5 times sqrt(3)
so 6x5xsqrt(3)= 30 sqrt(3)
Simplify.
5 times the square root of 75