Hi Nancy;
Tina looks out into the barnyard and sees pigs, chickens and ducks. She counts 38 heads and 86 feet. Knowing that that the sum of the number of pigs and chickens is 2 more than the number of ducks. (all animals are normaleach has 1 head, etc) set up the using algebra equations and solve.
FIRST EQUATION...P+C+D=38
4P+2C+2D=86
SECOND EQUATION...2P+C+D=43
P+C=D+2
THIRD EQUATION...P+CD=2

SECOND EQUATION...2P+C+D=43
FIRST EQUATION...P+C+D=38
Let's subtract the first equation from the second...
P=5
SECOND EQUATION...2(5)+C+D=43
SECOND EQUATION...10+C+D=43
THIRD EQUATION...P+CD=2
THIRD EQUATION...5+CD=2
Let's add the second and third equations...
15+2C+0=45
Let's subtract 15 from both sides..
2C=30
Let's divide both sides by 2...
C=15
FIRST EQUATION...P+C+D=38
5+15+D=38
20+D=38
D=18
SECOND EQUATION...2P+C+D=43
2(5)+15+18=43
10+15+18=43
25+18=43
43=43
THIRD EQUATION..P+CD=2
5+1518=2
2018=2
2=2
12/22/2013

Vivian L.