Answer :

Certainly! Let's simplify the given expression step-by-step:

[tex]\[ -15 \sqrt{x} + 4 \sqrt{y} - \sqrt{x} - 7 \sqrt{y} \][/tex]

1. Group like terms:
The terms involving [tex]\(\sqrt{x}\)[/tex] are [tex]\(-15 \sqrt{x}\)[/tex] and [tex]\(-\sqrt{x}\)[/tex].
The terms involving [tex]\(\sqrt{y}\)[/tex] are [tex]\(4 \sqrt{y}\)[/tex] and [tex]\(-7 \sqrt{y}\)[/tex].

2. Combine coefficients of [tex]\(\sqrt{x}\)[/tex]:
[tex]\[ -15 \sqrt{x} - \sqrt{x} = (-15 - 1) \sqrt{x} = -16 \sqrt{x} \][/tex]

3. Combine coefficients of [tex]\(\sqrt{y}\)[/tex]:
[tex]\[ 4 \sqrt{y} - 7 \sqrt{y} = (4 - 7) \sqrt{y} = -3 \sqrt{y} \][/tex]

4. Write the simplified expression:
Combine the results from the above steps:
[tex]\[ -16 \sqrt{x} - 3 \sqrt{y} \][/tex]

Thus, the simplified expression is:

[tex]\[ \boxed{-16 \sqrt{x} - 3 \sqrt{y}} \][/tex]