For questions like this just multiply the prices by how many they're buying and add all the numbers up and subtract by how much they have to begin with.
Example:
$34.99×2=$69.98
$16.50×3=$49.50
$3.75×4=$15
$69.98+$49.50+$15=$134.48
$134.48-$125=$9.48
Answer:
the answer is 3 hope this helps
x -3y = 4 multiplie both sides by -2 => -2x +6y = -8
2x +Qy = 8
-2x +6y = -8
2x +Qy = 8
------------------ assume the same terms
0 6y +Qy = 0
6y +Qy = 0
Qy = -6y divide both sides by y and will get
Q = -6