help please.really need help.?

Question

1) Mary paid $2100.00 for a pair of parrots and 3 dogs.If she had bought one more and 2 fewer parrots,she would have paid $200.00 more.Calculate the cost of (i) a dog, (ii) a parrot.

Answer 1

x=price dog
y= price parrot

Given:
2*y+3*x=2100 (a)
0*y+4*x=2300=>4*x=2300=>x=575$

fill x in (a): 2*y+3*575=2100=>2*y=375=>y=187.5$

Answer 2

Each dog costs $575, each parrot costs $187.50