so let's check the prices at both places.
Palanzio's
6.80 + 0.90(1)........... 1 topping
6.80 + 0.90(2)........... 2 toppings
6.80 + 0.90(3)........... 3 toppings
6.80 + 0.90(x)........... x toppings
Guido's
7.30 + 0.65(1)............1 topping
7.30 + 0.65(2)............2 toppings
7.30 + 0.65(3)............3 toppings
7.30 + 0.65(x)............x toppings
so, that is the cost equation for each one, now, if the costs were to be the same, then 6.80 + 0.90x = 7.30 + 0.65x, what's x?