Identify the terms in the expression 5x−3x+12

Ashopper bought a watermelon a pack of napkins and some paper plates in his state there was no tax on food the tax rate on non-food items is 5% the total for the three items he bought was 825 before tags and he paid $0.19 in taxes how much did the watermelon cost

What is the value of x? enter your answer in the box. photo attached.

Una caja de galletas contiene 16 paquetes y cada una de estas tiene 12 galletas y se quieren repartir entre 6 niños ¿de cuantas galletas le toca a cada niño?