a) 100 + 15x
to find out the equation for the first part, we know that the cost of the banquet room for an event is $100. to add, for each guest (x), we add another $15, which means you have to multiply the price of each guest with the number of guests (x)
to find out part (b), you have to substitute x as 20 in the equation and you shall arrive at the answer of $400
how many animals are there
17 cats + 24 dogs + 3 fish + 4 hamsters = 48 pets
to find the percent, we take the number of dogs over the total number of animals
percent dogs = 24 dogs/ 48 animals = 1/2 = 50 %
you went wrong on the 4th line while expanding the parentheses.
(x^2 + 2x)(x^2 + 2x) - 4
= x^4 + 2x^3 + 2x^3 + 4x^2 - 4
= x^4 + 4x^3 + 4x^2 - 4. (answer).