Verified Answer :

7y^2 - y^2 = 6y^2 i think!

Hey there...
Let's solve this problem by steps.

Method 1 -
Step 1 --> Taking GCF
\(y^2 ( 7 - 1 )\)

Step 2 ---> Combining like terms
\(y^2 ( 6)\)

Or

\(6y^2\)  is your final answer.

Method 2 -
We can straight way subtract \(y^2\) from \(7y^2\) which is
\(7y^2 - y^2\)
\(=\ \textgreater \ 6y^2\) 

Hope it helped you..  :)