Fill in the blanks. some examples are provided

Scarlet bought three pairs of sunglasses and two shirts for $81 and paula bought one pair of sunglasses and five shirts for $105 what is the cost of one pair of sunglasses and one shirt?

F(x)=x/2-2 and g(x)=2x^2+x-3 find (f+g)(x)

Whit h equation best represents this situation the number 98 increased by an unknown number equal to 120