Posted by john on Friday, October 5, 2012 at 9:29pm.
Today we learned how to solve systems of equations with 3 variables, however my teacher didn't go over how to do a problem where not every single equation in the system has the 3 variables. Can someone point me to a place that explains this?
the kind of problem im talking about is like this
solve the system of equations:
6a2b=18
3b+5c=34
a+6c=28

Alg 2  Reiny, Friday, October 5, 2012 at 11:31pm
notice that each of the equations is missing a different variable.
If we can eliminate the variable "a" from the 1st and 3rd, we have a new equation with b's and c's like the 2nd equation
so. from the 3rd a = 6c  28
sub that into the 1st
6(6c  28)  2b = 18
36c  168  2b = 18
36c + 2b = 186
b + 18c = 93
let's multiply that by 3
3b + 54c = 279
subtract the 2nd
49c = 245
c = 5
then a = 6(5)  28 = 2
and
3b + 5(5) = 34
3b = 9
b = 3
a = 2 , b = 3 , c = 5
Answer This Question
Related Questions
 algebra 2  i'm trying to solve this system of equations with 3 variables 5ab+...
 math  How do you solve system of equations and tell if they're consistant and ...
 math  Can someone correct this for me please or help me out.... Why are ...
 Algebra question  When you solve a system of equations by the substitution ...
 Algebra 2  1.) Write a system of equations that has NO solution. 2.) If you ...
 Algebra 2  1.) Write a system of equations that has NO solution. 2.) If you ...
 Algebra 2  1.) Write a system of equations that has NO solution. 2.) If you ...
 Algebra  Translate each problem into a system of equations. DO NOT attempt to ...
 Math  PLEASE CHACK MY ANSWER!!! Discussion for Applications of Linear Systems ...
 Algebra II  Right now we're doing systems of Linear Equations in Three ...
More Related Questions