You would multiply the two terms which are -6y^2 and -13x^2*y^5.
Multiplying -6 by -13 yields 78, which will be the new coefficient.
Since there is only the x^2 from the second term, that remains the same. However, there are two y values that we can multiply together: y^2 and y^5. y^2 * y^5 = y^(2 + 5) = y^7.
Therefore, your answer is 78x^2*y^7.